Nico di Angelo

NiccoloThe Sun and the Star page 21 "Nico" di Angelo is a 15-year-old Rick Riordan's Instagram Italian-born Greek demigod, the son of Hades and Maria Di Angelo. He is a main character in the Percy Jackson and the Olympians, The Heroes of Olympus, and The Trials of Apollo series of books and the protagonist of The Sun and the Star: A Nico di Angelo Adventure. Nico is the younger brother of the late Bianca Di Angelo and the paternal half-brother of Hazel Levesque. He's known in the Underworld as the "Ghost King" after taking the title from Minos in The Battle of the Labyrinth. He is currently in a relationship with Will Solace.
==History==
===Early Life===
Nico di Angelo was born around 1929 on January 28th in Venice, Italy, before World War II (before Hades and his brothers took an oath to have no more demigod children) to Hades and Maria di Angelo, their second child together, the first being his older sister Bianca di Angelo. He was raised in a conservative catholic home. 
Hades rarely made appearances in the household, in fear that the other gods would notice that he had a son and a daughter. 
As a child, Nico was obsessed with pirates and the game Mythomagic, which caused him to find the knowledge of being a demigod very exciting. At around the age of six, Nico visited Diocletian's Palace in Split, Croatia.
Nico had a warm relationship with his mother, as he remembers her smiling down at him while they both walked by the Venetian Grand Canal.
In elementary school he studied Dante.
===Relocation and Losing his Mother===
At some point near the beginning of World War II, Nico and his family left Italy for the United States, where they stayed at a fancy hotel in Washington, D.C.. Shortly after arriving, Nico was playing Mythomagic with another boy his age, Henry Whittaker, and he mentioned that Ares was pretty. Henry said that was weird and they stopped hanging out.
One day, as Hades was begging his mother to store him and Bianca somewhere safe as Zeus was planning to kill them. Shortly after, she died when Zeus struck the hotel they were staying in with lightning in an attempt to kill the siblings since he thought they would be to dangerous. However, they were protected by Hades as he erected an impenetrable wall of black energy to shield them from Zeus' bolts, but Hades was not able to protect their mother in time.
Afterward, a devastated Hades ordered the Fury Alecto to take Nico and Bianca to the Underworld and bathe them in the River Lethe, in order to wipe away their memories and told her to give their mom the Ancient rites. The lord of the dead also swore revenge on Zeus. This later caused him to send monsters to attack and try to kill Thalia Grace, Zeus' daughter.
===Washington D.C. and the Lotus Hotel and Casino===
In The Titan's Curse, Bianca says that she and Nico had no memories of their mortal parent and told by a lawyer (Alecto in disguise), in Washington D.C., that their parents were dead, and had left a bank trust for them. This "lawyer" would come by once in a while to check on both of them. During this time, Nico and Bianca were enrolled in a boarding school. Meanwhile, Bianca familiarized herself with the city's subway system. In The Blood of Olympus, Nico sees a brief flashback from this time - his sister Bianca, laughing as she pulled him across the National Mall. After some time had passed, Hades, hoping that one of his children might one day become the "child of the Eldest Gods" (referred to in the Great Prophecy), decided to place them in the Lotus Hotel and Casino, and tasked Alecto with the job. Once again disguised as a lawyer, Alecto had Nico and Bianca leave the boarding school, and took them all the way to the Lotus Hotel, in Las Vegas.
After what the siblings thought was a month in the Lotus Hotel (which turned out to be 70 years), they were taken out by Alecto, this time disguised as a different lawyer. Alecto drove Nico and Bianca back east, through D.C., and then up into Maine. They were brought to a military school called Westover Hall, paid for by Hades using what Nico and Bianca thought to be a trust fund left to them by their parents. At this point, Nico became obsessed with Mythomagic, a card game. It was later revealed that Nico had been obsessed with pirates even before he started collecting Mythomagic cards. Bianca mentioned that the summer before she left Westover Hall (during the events of The Sea of Monsters), she and Nico visited Washington D.C. once again, and were very surprised to see several subway stations that had not been there before. Bianca mentions that during their visit, several monsters (disguised as mortals) attempted to attack them in an alley. Nico also mentions seeing a bus driver (most likely a satyr in disguise) with ram's horns, though Bianca had not believed him at the time. 
==Percy Jackson and the Olympians==
===The Titan's Curse===
Spoiler alert. Hit "Expand" if you want to continue anyways.
Nico and his sister, Bianca di Angelo, appear at a school dance at Westover Hall, a boarding school in Bar Harbor, Maine. Grover explained to Percy, Annabeth, Jem and Thalia that he’d discovered them at school but every time he tries going near them, Dr. Thorn keeps blocking him. They saw them arguing on the bleachers, with Nico playing with Mythomagic cards. Bianca and Nico were later taken by Dr. Thorn, scared of Percy. Dr. Thorn tried to kidnap them and Nico stood up for Bianca when Dr. Thorn called her an “insufferable girl”. Percy tried defending the siblings and Thalia and Annabeth later jumped in to defend them. Nico got excited when he found out Dr. Thorn was a Manticore, saying he had 3,000 attack powers and 5 saving throws.
After they were saved, Percy told Nico and Bianca that they were demigods, and Nico thought it was cool, and immediately asked questions about Zeus. Nico also complimented Percy about how he attacked the manticore. Nico was also excited after he heard about Camp Half-Blood and immediately wanted to go. While Artemis spoke to Bianca, Nico went to talk to Grover in the woods about “geeky stuff”. When they came back, Nico exclaimed that Percy’s arm was green while Grover healed it. Nico also showed Percy his collection of Mythomagic cards and figurines and asked to see his sword. Nico immediately asked Percy a lot of questions, annoying him, including if asking if Annabeth was his girlfriend. Percy almost lost his cool until Zoë Nightshade asked to see Percy.
Bianca talked to Nico explaining her decision to join the Hunters of Artemis, making Nico upset and gloomy. However, Nico was impressed with Apollo and said he had a cool car. When they got on the bus, Bianca left Nico to sit in the front of the bus with Percy, Thalia, Grover, and Apollo while she sat with the Hunters. Nico asked Apollo a lot of questions about the gods and the sun, making Apollo laugh and ruffle Nico’s hair and answer them, not making sense to Nico. Nico asked if he could drive the car, but Apollo said he was too young.
When they arrived at Camp, Nico asked Percy about the lava climbing wall. Bianca whispered something in Nico’s ear, but he scowled and looked away, making Percy wonder what Bianca told him. He also asked who Chiron was, and said he didn’t have his figurine. Percy explained it to him, and Nico said if the Hunters didn’t like him, it was good enough for him. Percy introduced Nico to Chiron and Dionysus and was taken by Grover to see the orientation film, after asking what rating it was, since Bianca was strict. Later, Nico was impressed when finding out that Chiron was a centaur. Nico was also impressed by Dionysus and called him “the wine dude”, after saying he had his figurine in Mythomagic, and talked to him about the defence points all the gods had in the game.
At dinner, Nico sat with Connor and Travis Stoll at the Hermes cabin table, telling him poker was a better game than Mythomagic. The next day, Nico played Capture the Flag on a team with Percy, the Stoll Brothers, Charles Beckendorf, Silena Beauregard, and some others. Nico ran up to Percy before the game started telling him the game was awesome, with a helmet too big for him. Nico asked if he could kill the other team, but Percy told him it was serious and that swords could hurt. Nico took guard duty with the Stolls and Beckendorf and cheered when Percy crossed the boundary line.
The next day, Percy found Nico spying on Bianca and Zoë arguing about what happened to Phoebe in the early morning. Nico later saw Percy after he removed the invisibility cap, and thought it was cool. Nico told Percy he didn’t sleep too well and wanted to follow Bianca on to the quest, but Percy said he couldn’t because she could die, making Nico say Percy could go for him. Nico and Percy argued until Nico asked if he was planning to go anyway, and Percy said yes. Nico said he wouldn’t tell on him, but he had to promise he had to keep Bianca safe. Percy promised, and Nico said he would make an excuse up to Chiron, and told him to go.
A few days later, Nico ran to find Percy in the Big House and asked where Bianca was. Percy told Nico the news and gave Nico the figurine she wanted him to have. Nico said that he promised to protect her, and though Percy tried to explain, Nico said that he promised. Nico said he shouldn’t have trusted Percy and explained his nightmares and said he hated him, throwing the statue. Nico said he could feel Bianca being judged in the Fields of Asphodel, but skeletons interrupted them. Nico opened a crack in the floor of the cabin, making the skeletons disappear. Nico told Percy that he hated him and wished he was dead, and ran away. Percy realized he was a son of Hades and told Grover and Annabeth, but not Chiron.
Another reason Nico ran away was for love. He had a crush on Percy and couldn’t deal with the feelings towards him, and ran away. Homosexuality was illegal in the 1940s, so he felt great shame for his feelings. He couldn't imagine a man he trusted hurting him and was angry at him for what happened to Bianca, but his feelings for his hero complicated that.
===Hiding in the Labyrinth===
Nico eventually found the entrance to the Labyrinth and found Minos. Minos manipulated Nico and the two traveled together, with Nico barely eating at all. Nico became very depressed during this time and his anger only grew bigger, and he became convinced that he would never belong at Camp Half-Blood because he was a son of Hades. He even abandoned his Mythomagic cards. Nico became very strong during his months away, learning to summon ghosts. He also got his Stygian Iron sword. Nico also learned how to shadow travel but ended up in China many times. Nico and Minos would camp out in the Underworld where Minos would try to manipulate him into doing a soul for a soul to bring Bianca back.
Nico’s appearance also changed. His hair grew to his shoulders and his skin went from olive to as white as snow. He also donned his signature outfit of his aviators jacket, black jeans, and a skull shirt, with a sword on his side. He became very skinny and bony due to his meager diet.
While Nico was gone, Percy, Grover, and Annabeth searched for him the entire spring with no luck. Percy thought about Nico a lot and the crack he made, which, was still at the Dining Pavilion.
===The Battle of the Labyrinth===
Spoiler alert. Hit "Expand" if you want to continue anyways.
Percy found Nico through an Iris Message sent by Bianca. He found Nico camping in the Underworld along the banks of the River Styx, with Minos. He was ripping his Mythomagic cards and throwing them into the River, wondering why he used to like them. Minos agreed that it was a childish game. Nico felt guilty that there was no way to get Bianca back, but Minos suggested yet again that he do a soul for a soul for someone who cheated death. Nico was against doing it, since it was murder. He asked him why he couldn't just summon Bianca. But Minos insisted that he should get revenge, and that he owes him after everything he did for him. A tear fell down Nico's cheek and he agreed to do it. 
The next day, Percy was sent another message to Nico. This time he was digging a hole in a graveyard to summon a ghost. He emptied a few coke packs and McDonald's happy meals so the ghosts would respect him. But ghosts know that McDonald's is cheap and gross so it didn’t work. Minos didn't get why he used animal blood but Nico said he wanted to treat the dead with respect. He summoned many ghosts and the first one to speak was Theseus, the Greek hero. He asked how he could bring his sister back but Theseus said to not try, it was madness. He reluctantly gave advice until he told Nico to release them, and that "he was coming". 
Later, Nico unexpectedly meets Percy, Annabeth, Tyson, and Grover at the Triple G Ranch. He'd entered the ranch to discuss finding the soul he needed with Geryon. Percy and his friends went to the ranch due to the chance Nico might be there. When Nico sees them, he is furious, pulled out his sword, and said they let Bianca die and they will kill him as well, but Percy reassured him that was not the case. Though he was still angry, he put away the sword after Geryon ordered him to, but told Percy to not come near him or his helpers would hurt him. Later, Nico became angry at Geryon after he showed him and the others his stables instead of discussing the soul he needed. Percy tried to ask him about it but Nico refused to give information, only saying it wasn't Percy. Geryon ended up imprisoning Nico and the others, threatening to sell Nico to Luke Castellan unless Percy cleaned his stables. Nico didn't want Percy to save him but he did anyway. 
After he was saved, Percy tried to tell him to stay at the ranch for his safety, but Nico yelled at Percy him what happened with Bianca, causing Annabeth to come to his defense. After arguing, Percy decided to help Nico summon Bianca's soul after Nico couldn't, telling him she sent him iris messages. That night, they went into the field to summon her, but it was interrupted by Minos, telling Nico to not trust Percy and his friends. Nico managed to order Minos to leave and the ritual continued. Bianca appeared, and Nico was overjoyed to see her, but she was sad, saying he gotten tall. Nico was heartbroken when she said that he hoped he'd given up on summoning her, saying Percy was right and he cannot hold grudges, since they were the fatal flaw for children of Hades. Nico became angry at her for helping Percy, but Bianca told him to stop blaming him for her choices, since she knows he is mad at her, and that it would be his doom. Bianca disappeared after Kronos stirred, saying she loved him and to remember what she said. 
Nico didn't sleep much that night, since the next morning he had red eyes and a chalky face. Before he left, Percy said his goodbyes to Nico, saying he could come with them. Nico said he needed time to think and wouldn't meet Percy's eyes, still a little angry at him. Annabeth put her hand on his shoulder and tried to comfort him, but he walked away. Percy and his friends were worried for him but Eurytion reassured them that he would be alright. 
However, Nico was tricked by Minos to return to the maze under the ruse that Percy was in danger, which Annabeth found out about after Eurytion told her. Orthus tried to track his scent but to no avail. He ended up being taken prisoner and dragged to Daedalus's Workshop by Kelli, two laistrygonians, and Minos. Nico apologized to Percy and explained he was told he was in danger but was tricked, to be turned in to Kronos. As they attacked Kelli, Nico struggled with his chains and was pushed to the ground. Nico managed to rise up and break from his chains and defeated Minos, declaring himself the ghost king, causing the windows to shatter and Minos and his friends be summoned back to the underworld. Nico then escaped with Percy, Annabeth, Jackie, and Rachel Elizabeth Dare. 
They landed at Pikes Peak and Nico told the group that he knew Daedalus wasn't dead, but he wasn't sure about Tyson and Grover. He then followed Annabeth to the gift shop to get food. After that, the four returned to the maze and Nico walked behind with Percy. Percy thanked him for helping them and Nico explained that he owed him for saving him, and Daedalus should die for avoiding death too long. He then explained he knows he will never be accepted at camp and only the dead respect him. Percy tried to tell him he'd have friends at camp but Nico asked if he really believed that. Percy couldn't answer, since Nico was scary and sometimes made him uncomfortable. The group then stopped at Mount Othrys, and Nico stayed behind with Rachel and Annabeth as Percy went in. The only thing the three could agree on was to save Percy, and saved everyone by making a fissure of rock rise and made the columns of Othrys fall. Percy told him he revealed himself as a son of Hades, but he brushed him off. 
After that, they all met up with Tyson and Grover and all ended up in the home of Pan, rendering Nico speechless. Pan explained that he should've died long ago, and said Nico understood that. Nico explained he was dying and should've died long ago. Pan addressed all of them, except for Nico, and he faded away. They then left the cavern and prepared to return to Camp, but Blackjack didn't want him to ride him. Nico told them to return to camp without him, but he agreed after Annabeth insisted, possibly to make Percy jealous.
Nico fought bravely in the Battle of the Labyrinth, stabbing a telkhine and summoning many ghosts. This act weakened him and he crumpled to his knees. After the battle, Tyson beckoned Percy and Annabeth to help Nico, who's clothes were smoking. Nico was healed with nectar and said he never summoned that many before, but he would be fine. They all then headed over to Daedalus, who told Nico he could hold his soul for ransom and use it to bring Bianca back. But Nico refused, saying he will release Daedalus but Bianca had passed on. After he addressed everyone, Nico released him.
That night, Chiron offered that Nico could sit with him, but he refused and went into the forest to say goodbye to Bianca. Percy found him, and Nico told him that he was saying goodbye to Bianca. Percy said he could've sat with him at dinner and he cannot miss every meal, but Nico said he wasn't staying. Percy protested but he explained that he didn't belong at Camp and needed to find out about his past. Percy wanted to argue, but knew he had to find his own dark way. Percy said he hoped they wouldn't be enemies, and Nico apologized for being a brat, saying he should've listened to him. Percy then gave Nico the action figure Bianca got him, but he didn't want it, saying the game was for kids. But after Percy said it had 1,000 attack power Nico corrected him, saying 5,000, and Percy said he can still be a kid once and awhile, causing him to accept the action figure. Nico promised he'd tell him anything useful and they shook hands before he left.
A few months later, Nico appeared in Percy's fire escape on his birthday to tell him about his plan. He told him Daedalus got his punishment and was about to tell him his plan when he saw blue cake and questioned it. Percy realized he hadn't been to a birthday party before and invited him inside for cake and ice cream, saying they had a lot to discuss.
===The Demigod Files===
====The Sword of Hades====
Nico is one of the three demigods along with Thalia and Percy who are summoned by his step-mother Persephone to find the Sword of Hades. When he is first summoned by Persephone he claims to have been at a graveyard in New Orleans, this could possibly be reference to Hazel. Naturally, Nico didn't take well to her welcome since she turned him into a dandelion when they last met. Percy thinks it's a bad idea but Nico is hoping to achieve recognition from his father Hades. He tells Thalia and Percy why they need to go on the quest. To Percy's irritation, he comes up with logical reasons. His knowledge of the Underworld and its occupants helps them complete their quest. He remains in the Underworld afterward to discuss the upcoming Titan War with his father. Before his friends leave, he reminds Percy of his idea to defeat the Titans. 
===The Last Olympian===
Spoiler alert. Hit "Expand" if you want to continue anyways.
Nico's theory to gain an edge over the Titans is finally revealed: it is to make Percy invincible by having him bathe in the River Styx, similar to the myth of Achilles. In The Blood of Olympus, it is revealed that Nico knew Percy would not like the plan and worried over how it would affect their relationship, sarcastically saying Percy would "really love him for that". It is shown that after Bianca died, Hades believes that he has no competent child, repeatedly mentioning that Bianca could do a better job at fulfilling their father's demands. At some point earlier, Nico began preparing for his plan, and did some research on Luke's past, and had found May Castellan, his mother.
Later on, Nico is once more searching for information about his mother and childhood, a quest that brought him to Mount Othrys/ Olympus. Nico is first seen there in Percy's dream, using a chance to eavesdrop on the Titans Hyperion and Krios, as well as the imprisoned Atlas. It is later confirmed that this was true. Shortly after Beckendorf sacrifices his life to destroy Kronos's ship so that Percy could escape and the enemy ship could be destroyed, Nico speaks to his ghost and learns that Beckendorf will go to Elysium. Nico himself also heard the lines of the Great Prophecy, presumably from another ghost, or Hades himself. 
Later on, Nico arrives at Camp Half-Blood by shadow travel, which initially terrifies Juniper and Leneus, and he briefly discusses Grover's disappearance with them, after which he encounters Percy. Nico is finally able to persuade him to go through with their plan, and both of them and Mrs. O'Leary shadow-travel to Luke's old house to meet his mother, May Castellan. Afterward, they briefly encounter the goddess Hestia, who greets them warmly and offers them food.
Soon after, the three enter the Underworld, where Nico, who wasn't telling Percy everything, had the Furies carry them to Hades' Palace. It is revealed, that in order to gain information about his past and his mother, Nico had to bring Percy to Hades in exchange. Nico had no ill intentions, and only agreed after making Hades promise not to harm his friend. His father reveals that the lawyer who removed Nico and Bianca from the Lotus Hotel and Casino was the Fury, Alecto, in disguise, but refuses to give him details on his mother's death. After Hades still imprisons Percy in his dungeons, Nico helps him break out, apologizes, and still follows through with his initial plan of having Percy bathe in the Styx and gain the Curse of Achilles. After Percy bathed in the Styx and got the Curse of Achilles, he was able to defeat Hades and his entire army of the dead, leaving Nico shell-shocked.
Later, Nico attempts to summon the ghost of his mother, but Bianca's ghost appears and tells him not to. He sees the scene of their mother's death in which Zeus blasted the hotel she, Hades, and the children were in into pieces. Hades, who realized what was happening too late, only managed to save Nico and Bianca. He then orders Alecto to wipe the memories of the children in the Lethe, including their mother's death.
By viewing this scene, Nico finds out who his mother is and returns to Hades' palace. In The Blood of Olympus, it is revealed in a conversation between Hades and Nico that during this time, Nico had repeatedly asked and begged his father to help Percy and the rest of Camp Half-Blood in the Battle of Manhattan. Hades said he'd never been so 'harassed' by one of his sons and suspected Nico had feelings for Percy. In the end, Nico is able to convince his father Hades to help the campers in the battle against the Titans.
Nico is the first to join the Battle of Manhattan, and fearlessly yells out a challenge to Kronos himself. Nico is soon joined by Hades himself, and they both summon wave after wave of the undead soldiers, who confront and eventually overwhelm Kronos' forces. After the Titan Lord is defeated by Percy and Luke, who sacrifices himself, Nico accompanies his father to Olympus and sits at his father's feet when Percy and his friends are receiving gifts from the Olympians. Apparently, Nico, through his unwavering loyalty and bravery in battle, has finally gained his father's pride, as Hades even pats Nico on the shoulder, and, according to Percy, this is "the happiest he's ever seen him." Since Hades is now accepted on Olympus, and Nico is accepted at Camp Half-Blood, Rachel is finally able to break Hades' curse on the Oracle and become the next Oracle of Delphi herself. Apparently, almost all campers are in awe of Nico's fighting in the Battle of Manhattan, as "even the Ares kids considered him cool." Nico is last seen when he orders undead workers to build the Hades cabin, made up of solid black obsidian walls with a skull over the door. There are torches inside that blaze with burning green fire that will never extinguish.
==Between the Series==
Sadly, Nico's popularity only lasted a few weeks. After that campers did whatever they could to avoid him and forgot he was at camp. (Though a year or so later Will Solace tells him this never happened, he in fact isolated himself). The fact that Percy had begun dating Annabeth did not make Nico feel any better. As a result, Nico takes to only showing up at Camp from time to time. Sometime after the Battle of Manhattan, Hades gave Nico a French zombie chauffeur, Jules-Albert, for his birthday.
As revealed in The Son of Neptune, in the September following the Battle of Manhattan, after Thanatos had been captured, and the dead were returning to the world, Nico had gone to the Underworld in hopes of rescuing his sister Bianca, but was unable to do so, because she decided to be reborn and thus couldn't be brought back to life.
Instead, Nico found his half-sister Hazel Levesque in the Fields of Asphodel and sensed she was a child of the Underworld, as, unlike the other souls in Asphodel, she remembered her life. Nico felt that she deserved another chance at being a hero and brought her to the overworld (Gaea said that he had selfish reasons for doing this, but it is unknown if he had any or for what selfish reasons did he do it for, maybe because he wanted a chance at having a sister again). Hades gives Nico directions on how to find Camp Jupiter, explains why the Olympians have kept both camps separated for centuries, and forbids him from telling anybody about it, as the time isn't right. Hades also advises his son to introduce himself to the Romans as a son of Pluto, telling Nico that it is important for him to make this connection.
As stated by Dakota, Nico took Hazel directly to Camp Jupiter and requested that Reyna and Jason take her in. Thus, Nico became the first Greek demigod since the First Demigod Civil War to learn about the existence of Roman demigods and to visit Camp Jupiter. He accepts a role as the Ambassador of Pluto to the Romans and becomes involved in the camp's political life as a Senator.
==The Heroes of Olympus==
===The Lost Hero===
Annabeth mentions that Nico is searching for Percy along with Tyson, Grover, and the Hunters of Artemis, but otherwise, he doesn't appear in this book. It's to be assumed that he doesn't stay at Camp Half-Blood much, as Annabeth said he "sometimes" shows up, which could be due to his double duty at Camp Jupiter as Ambassador of Pluto. She mentions him as one of the only children of the Big Three along with Percy Jackson, Jackie Asturias and Thalia Grace. Unknown to her, Jason Grace and Hazel Levesque are also children of the Roman Big Three, being the son of Jupiter and the daughter of Pluto respectively.
===The Son of Neptune===
To see this text, hit the "Expand" link to the right.
Nico meets Percy at Camp Jupiter, where he is visiting his half-sister, Hazel Levesque. Nico is very shocked when he sees Percy, but he introduced himself and held out his hand. They shook hands, and Percy said that he knew him, but Nico said, “Do you?”, not telling him about his past. Hazel tells Nico about how Percy arrived and Nico tells Percy about Gaea, and how evil she was. He also tells him about how. Saturn came back and caused the Second Titan War and the Battle of Mount Othrys. Nico mentions how he told Reyna Ramírez-Arellano about the giants being reborn, but she didn't listen to him. Nico also greeted Frank Zhang when he arrived and smiled since he was amused by him and was never uneasy around him. Nico tells Frank to take Percy to dinner while he talks to Hazel, and tells Hazel that he is staying overnight. Hazel is stressed about this because she knows that the campers won’t like that.
Hazel and Nico talked on the roof of Pluto's Shrine, where Nico tells Hazel that important things are at work, and he cannot tell Hazel much about Percy, but she can trust him because he is only dangerous to his enemies. Hazel was still suspicious, and Nico got moody, making bones pop up from the ground. Nico reassured Hazel that she can make things right, and almost calls her Bianca, making Hazel even more bitter, knowing that she will never be like her. Nico tells Hazel how "Pluto" was going crazy because of everything happening in the Underworld, and that Hazel belonged at Camp Jupiter. After Hazel blacks out, Nico gets very worried and asks her where she was when she woke up. Nico warns Hazel that she should better control her blackouts. He and Hazel ran to the mess hall for dinner and Nico gave her Nectar to heal her cuts after she fell when a gold bar popped up. The two ran for the gates of Camp to not be late for roll call. When they arrived, Nico went next to Percy. After Hazel stood for Percy, Nico was proud of her and beamed at her, calling her "sis". Hazel wondered if he called Bianca that. While Frank was with Percy, Percy asked many questions about Nico, which Frank didn’t know much of the answers. Frank thinks that he isn't like Hazel since Hazel is nicer and better looking, and tells Percy that he is mysterious and makes everyone nervous, but not him. At dinner, Nico sat with Frank, Percy, Hazel, and the Centurion Dakota. Percy wanted to talk to Nico about if he saw him before, and Nico panicked and told him unless he saw him in the Underworld, they never saw each other. Dakota says how Reyna never knows what to do when Nico arrives, which Nico took no offense to. Nico says that Dakota was helpful, standing for Hazel, making Dakota blush. Nico tells Percy that he only learned about Hazel recently, how children of Pluto stick together, and how he had another sister. When Don started mentioning Percy's Empathy Link, Nico had Frank and Hazel get Percy oriented and dragged Dakota, Don, and Vitellius to the Praetor's table to discuss war strategies, dragging Don and Vitellius by the ear.
During the War Games, Nico watched from the observation tower in the fort with binoculars. After Gwendolyn died and came back to life, Reyna asked Nico if it was a power of Pluto, but Nico says that no one returns from the dead, and glanced at Hazel, telling her to stay quiet. When Mars arrived at Camp, he glared at Nico while talking about how some people return from the dead. The next day, Nico participated in the Senate meeting and wore a black toga, sitting with the other Senators. Nico tells Reyna that he and Hazel learned about the giants from Pluto, and how the eldest giant, Alcyoneus, was born to oppose Pluto. Reyna was suspicious, and told him that he sounded "quite familiar with him". Nico tells the others how only a demigod and a god together can kill a giant, and how it has happened before in the First Giant War. Nico also explains to Percy how Pluto is the god of the dead, but Thanatos is the god of death, but he was captured. Nico also says how it is easier for ghosts to escape your Underworld, and how Gaea and her forces captured the Doors of Death, making monsters escape.
Before Hazel left, Nico wished her luck and said that he would head back to your Underworld to help his father with helping the Furies. Nico also planned to track escaping souls and find the Doors of Death. Hazel told him to be careful, but Nico said that he knew how to hide. Nico was also worried that after she saved Thanatos, he would never see her again, and she would go back to the dead. Nico said goodbye and melted into the shadows. Nico is later shown in one of Hazel's flashback blackouts. He finds Hazel in the Fields of Asphodel and brings her back to the mortal world to give her another chance at life. Hazel later learns that he is in Rome. Percy becomes angry at him when he regains his memories.
===Journey through Tartarus and Europe===
As Nico is searching the Underworld for the Doors of Death, he finds the entrance to Tartarus. Not long after, he encounters the Chimera and Echidna, momentarily mistaking the later for his grandmother. After taunting the pair, they attack Nico and the son of Hades is pulled into Tartarus. After falling, Nico is surprised that none of his bones are broken and gets up. After spotting the Giant Army, Nico is spotted by wolves and runs. As the wolves are gaining on him, he sees a house nearby and someone waving at him. The son of Hades makes it to the house and he is greeted by Nemesis. Nemesis insists she is there to help Nico, but he does not believe it. The goddess takes the form of his father and tells him to correct the imbalances in his heart. She gives Nico pomegranate seeds from his step-mother’s garden and he questions the gesture. After saying she is weaker in Tartarus, the goddess tells Nico to follow the River Phlegethon downstream to reach the Doors of Death and to restore balance in his heart. The house and goddess vanish, but not before warning Nico of her mother, and Nico sees a bubble of puss. It bursts and an empousa emerges, he kills her as she complains that she just reformed and the son of Hades runs away. He finds the river of fire and follows the goddess’s instructions.
Nico follows the river of flames and, as he does, slowly loses his sanity and questions if he will die in Tartarus. Soon after reaching a forest, he gives into his thirst and drinks from the Phlegethon. To the son of Hades's utter shock, the river is cold and he survives drinking from it, feeling much better. Nico continues to follow it and finds the river bend at a right angle before a wall of darkness. Nico sees an archway and, thinking it is the Doors of Death, goes to it. He crosses and, upon realizing it is not the Doors of Death, he hears a mother and son talking. Nico tries to sneak away, but he is caught. Nico soon realizes he is before Nyx and Hypnos. Nyx interrogates Nico as Hypnos says he made a mistake coming to his mother’s domain. Nico tries to play dumb, but Nyx quickly realizes he is a demigod son of Hades and learns his name. Soon Ephialtes and Otis arrive and demand Nico. Nyx is reluctant to hand him over and Nico tries and fails to get the four to turn on each other. Nico manages to slip away, but becomes petrified at the sight of the Mansion of Night. He cries in despair and Nyx taunts him and agrees to the giant’s deal. As Nico is stuffed in a jar, Nyx says she wants to see him again if he survives.
The giant twins take him through the Doors and drag him through the House of Hades. They take him to Rome in the Coliseum where he would die on the Kalends of July. They use him as a trap to bait the Seven. Nico loses a lot of weight and ate pomegranate seeds, going into a death trance to breathe as little as possible. Nico almost gives up hope while in the jar.
===The Mark of Athena===
To see this text, hit the "Expand" link to the right.
Percy sees Nico in his dream, imprisoned in the jar in a coma-like state. He had marked three scratches on the wall of the jar, one for each pomegranate seed he had eaten. The seeds are a last resort food, which only children of Hades/Pluto can eat. Hazel explains that the seeds last for up to one day and put him in a death-like state so that he doesn't use up all his air, something Hazel calls a death trance. Piper mentions that the lines of the prophecy now makes sense: "Twins snuff out the angels breath, who holds the key to endless death." as Nico's last name is di Angelo, and 'Angelo' is Italian for 'angel'. Jason and Leo are wary of Nico and mention how he went between the camps, calling it 'shady' and questioning whether he is trustworthy. Hazel is outraged at this, saying Nico is her brother and saved her before storming out of the room. Ultimately, Jason and Leo apologize to her and the Seven agree that Nico is important to closing the Doors of Death and that they must save him. So, despite knowing that it's a trap, the Seven head to Rome to rescue Nico. After getting there, Hazel, Frank, and Leo try to find Nico, which leads them to the Pantheon, but they are led into a trap and are almost killed by eidolons. After defeating them, Leo realizes that Hazel was trying to track Nico by using his sword as a beacon, which they find lying in the workshop.
Instead, Percy, Jason, and Piper come to Nico's rescue underneath the Colosseum. During Percy and Jason's battle against Otis and Ephialtes, the jar Nico was held in breaks open and Nico falls out. Percy is shocked at his state and can't tell if he is alive or dead. Piper McLean manages to pull the incredibly weakened, but alive Nico to safety. Later back on the ship, Nico tells them how he was captured and what he now knows about the Doors of Death. Nico had found out that the Doors of Death have two sides: one in the mortal world and one in Tartarus. The mortal side of the portal is in Greece, at a temple called the House of Hades and it is guarded heavily by Gaea's forces. Nico then says that the other side of the doors is in Tartarus, a place not even the gods go and that is why Hades has not been able to close the doors. Not even the god of death, Thanatos, would go near Tartarus.
Leo guesses that the seven heroes will have to go to Tartarus and close that side of the portal, but Nico says that it would be impossible, and not even they would stand a chance down there because of the strength and the sheer number of monsters there. Percy then says that they can set sail for the House of Hades, defeat Gaea's forces, and close the doors on the mortal side. Nico, however, says that it is not that easy and that the Doors of Death have to be controlled on both sides to be closed, as they are like a double seal. He says that maybe all eight of them working together could defeat Gaea's forces on the mortal side, but that they would need a team fighting simultaneously on the Tartarus side; a team powerful enough to defeat a legion of monsters in their home territory.
In Arachne's lair, when Percy tries to save Annabeth from falling into Tartarus, Percy catches hold of a ledge just in time. Nico tries to help, but he is out of reach. Annabeth tells Percy to let go, but Percy says that he will not lose her again. Percy tells Nico that they will meet the rest of the seven and Nico on the other side of the Doors, and makes him promise to lead the others to the mortal side. Nico promises and Percy lets go, allowing the dark gravity of Tartarus to pull him and Annabeth in. During a meeting on the Argo II, Nico admits that Percy is the most powerful demigod he has ever met and with Annabeth there with him, they will survive. He believes that if anyone could make it through Tartarus, it would be them. He assures Leo that both Percy and Annabeth are still alive.
===The House of Hades===
Spoiler alert. Hit "Expand" if you want to continue anyways.
The Argo II is being attacked by numina montanums, or mountain gods, who are attacking with boulders. As they attack, a boulder hits the mast, causing it to collapse, and Nico, who was in the rigging, falls with it. Hazel Levesque runs to help Nico up from the debris, but he tells her he is fine. When Leo complains that masts don't grow on trees, Nico corrects him by saying that masts are made from trees, which only serves to annoy Leo further. Leo is forced to retreat again and the three try to think of an alternate way past the Earth gods. Nico explains that they don't like them because children of Hades/Pluto get under their skin but adds that the Athena Parthenos was most likely attracting more attention. When it is suggested that they take the Argo II around the mountains over the water, Nico explains that going that way is longer and without their sea expert, Percy, it might be too dangerous. Nico also complains that he is too weak to simply Shadow Travel the ship across the mountains. While coming up with ideas, Hazel tries to think of a way to help, not wanting her only contribution to be removing a dangerous obstacle Nico had told her was in the House of Hades. When Hazel prays to her father for help, Arion appears, running towards them. Nico asks who Arion is and is told by Leo that he is Hazel's horse. When Hazel comes back, Leo and Nico help her to her feet when she falls down. He asks her what she saw from Hecate, but Hazel refuses to tell him any information and tells him to get some rest.
Later on, Nico meets Jason, Leo, Frank, and Hazel for breakfast on the ship. Nico sat at the back of the table with his sword by his side, creeping Leo out. Nico tells the group how he met with a former priest of Hecate the night before, and he learned about things they need to do to go through the House of Hades, and the history behind the place. Leo made jokes about it but Jason told him to stop. While talking, the ship lurched and Nico fell against the wall, banging his head. Hazel rushed to help him, while Leo ran to help Piper and Gleeson Hedge.
The ship soon arrived in Venice, and Nico sat in the harbor with everyone else and surprised Frank by revealing he knows Italian. Nico volunteers to go with Frank to find the Black House and Hazel goes with, relieving a creeped out Frank. The three walk through Venice, while Nico led them to the house, and Nico mentioned that Venice was filled with Lemures and that his mother told him about it. Nico told the two that Hades met his mother in Venice in the 1930s and they had him and Bianca, but he doesn't remember much about Italy. Hazel and Nico were later attacked by monsters, and Hazel was poisoned, and Nico couldn’t stop it. Nico screamed for Frank and told him what had happened, making Frank wanting to kill the son of Hades. Nico told Frank to get back to the ship with Hazel, but a man leads them into The Black House. Nico finally remembers that the monsters were Katobleps, and said he knew them from Mythomagic. Frank tells Nico that he played that game but didn't have the card, and Nico says it was from the Africanus Extreme expansion deck. Nico begs the man to cure Hazel, but he refuses when he finds out that she is a child of Pluto. Nico begs more and is turned into a corn plant. Nico is later turned back to normal by him after Frank fixes his chariot, and Nico mentions having a strange nightmare about popcorn. Nico calls Frank brave for killing the monsters and is in shock when he realized he killed all of them but tried breaking the tension between Hazel and Frank by asking what barley looked like. After Nico was turned into a plant, Nico became more reclusive than usual and spent most of his time on the masts, away from the rest of the crew. Nico later discussed with the crew what to do about Sciron.
The Argo II arrived at Croatia to fetch Diocletian's Scepter. Nico mentioned the legend about the scepter and told Jason that he would need his help if he wanted to find it. Jason was creeped out by Nico but reluctantly decided to go with him. They arrived at Split, and after they saw a strange man, Jason picked up Nico and flew him to find how to get to Dalmatia, causing Nico to freak out about being touched. Nico mentioned how he visited Croatia when he was six, and being stuck in Lotus Hotel and Casino helped him transition easier since time passed in a weird way. He was at first reluctant about confiding in Jason, but eventually told him a bit about his past. They went underground and met Favonius, who told Nico that he was watching him since he was a little boy, and asked why he wouldn't allow the truth, with the person he cared about most in Tartarus. Jason thought it was Annabeth, and told him admitting his crush would be embarrassing, but it's for the scepter. In reality, Nico felt sick because he had to admit his crush on Percy.
Favonius turned them into the wind and took them to Dalmatia, and told Nico if he let anger rule him with Cupid, his fate will be sadder than his. When they land, Nico is terrified and braces himself against a rock, his legs trembling and grass dying under his feet. Jason, who still thinks he is in love with Annabeth, doesn't understand why he's so afraid. Nico stood by Jason when Cupid arrived, and for once, Jason was glad to have Nico there. Jason was pushed down the stairs, but Nico ran to help him up. Nico begged for the scepter after Cupid kept taunting Jason and eventually told him that he wants to pick on him, not Jason and that he doesn't scare him. Cupid taunted Nico, and told him to tell Jason why he left Camp Half-Blood, and why he is always alone, afraid of himself and his feelings, hiding among the dead. He tried to lie and say it was Annabeth and that he left because he didn't belong, but Cupid knew that wasn't the truth and continued to taunt him. Nico screamed, causing skeletons to come from the ground and memories of his life to be seen by Jason, who was shocked by the amount of pain he suffered and quickly realized Nico's feelings were for Percy, not Annabeth. Cupid also taunted him for running away from his friends, and Nico insisted he had none. Nico was nearly reduced to tears, and finally admitted that he had a crush on Percy. Cupid gave him the scepter and left, saying the only way to conquer love is to face it. Jason feels horrible for Nico and thinks Cupid is a cruel monster for forcing him to do such a thing. Jason told him that he won't tell the others, but that they wouldn't judge him and would "unleash the fury of the gods" on anyone that gave him trouble. Nico denied that he had a crush anymore, and said he was young and impressionable, his voice cracking. Jason remembers Nico is from the 1940s and can't imagine what it had been like for him all those years, keeping an unthinkable secret. Jason comforted him by saying out of everything he had seen, what Nico had done was the bravest. The two then went back to the ship.
After that experience, Nico hid even more from everyone, looking to Jason, Piper, and Leo as if expecting an attack from them. Piper knew something big happened in Croatia, but Jason wouldn't tell her. Nico put the scepter below deck, because the scepter was making the sea and weather weird.
Later Nico confronts Jason about leaving the palace of the Lord of the South Wind. Nico told him that he sensed Percy getting closer to the Doors and they needed to leave. He was annoyed that he couldn't convince Auster quicker and noted he had suffered too many humiliations to not make it in time. Jason attempts to talk to Nico about what happened previously, saying that the others won't judge him. Nico becomes angry and claims that as a son of Hades he would never be accepted anywhere and always judged, since the only one who accepted him was Bianca, and she died. He said that Jason would never understand, being a son of Jupiter and favored by everyone. He expressed frustration of having no say in his feelings and being gay. In his anger, the ground opens up and Nico seems to shimmer with ghostly light. Jason then challenges him by saying that he had just been running away and hiding for years, and that he should take a risk and believe that Jason really is his friend. As the scene reaches a climax, Nico tells Jason, "I'm going to honor my promise. I'll take you to Epirus. I'll help you close the Doors of Death. Then that's it. I'm leaving- forever." The son of Hades then disappears back into the shadows. Jason has stated multiple times that Nico di Angelo scares him when he gets angry, and began thinking befriending him was more trouble than it’s worth. Nico later went with everyone to Malta, where he met with Leo and shook his hand, happy to see him, and looked suspiciously at the people walking down the street.
Nico led Leo, Hazel, Frank, Jason, and Piper into the temple, and told the group it's going to get tough. Leo joked about it, annoying Nico. Nico ate the barley, and later gave the group the chalice of poison. He offers it to Jason first, telling him that he told him about taking a risk, and asked him how much he trusted him, and Jason drank it without hesitation. They walked through, and Nico could sense that the Doors of Death opened every twelve minutes and that Percy and Annabeth were in danger. They attacked my monsters, and summoned ghosts and tried to shout orders, but couldn't since he wasn't any Roman rank. Nico told Jason to promote Frank to the praetor, and he did, so Frank could control the ghosts. Frank yelled orders, and Nico genuinely smiled and laughed, saying "That's more like it. Let’s turn this tide!" Nico kept raising the dead and legionnaires with the scepter. When the battle ended, Nico calmly told Frank that he had an arrow in his arm. Nico, Jason, Piper, and Frank went to find Hazel and Leo and arrived with their swords drawn, and Nico used his sword to absorb the darkness. When the battle ended, Nico went to Hazel and kissed her forehead. Hazel cupped Nico's face, realizing that he had been crying. Nico had everyone hold hands and Shadow Travel away, with the help of Hazel. Nico realized he was holding Percy's hand and immediately pulled away.
Nico and the others ate dinner with Reyna, and Nico decided to go with Reyna and Hedge to bring the Athena Parthenos back to Camp Half-Blood and went to get ready. Nico tied the statue up with rope to attach to himself. In The Blood of Olympus, Nico recounts on a conversation with Annabeth he had on this day: Annabeth approached him, saying she needed to talk to him. Nico immediately panicked, thinking "she knows", meaning he was afraid she had found out he was gay, but she only thanked him. Later, Percy comes to thank him for keeping his promise. Nico says Percy doesn't have to thank him, and Percy is a little hurt that Nico is being so cold and distant. When Annabeth wishes him good luck, Percy notes that Nico wont meet her eye. He then shadow travels away with Reyna and Coach Hedge.
===The Blood of Olympus===
Spoiler alert. Hit "Expand" if you want to continue anyways.
Nico shadow traveled with Reyna and Hedge to Albania and something humiliating occurred, something they all agreed to never mention again. Two days later, he shadow travels himself, Reyna and Hedge into the air above Mount Vesuvius, and they nearly fall in, but Reyna lends him enough strength to Shadow Travel down into the city of Pompeii, after which he sleeps for about a day. When he finally wakes up just after sunset, he wolfs down a sandwich and talks with Hedge and Reyna about Reyna's dreams. He mentions that he thinks he could make it to Spain when Gaea possesses Hedge and sends dirt-encrusted ghosts of Pompeii to attack them. Reyna tells him to summon dead legionnaires to their aid with Diocletian's scepter, and he does so, but the scepter starts smoking and then explodes in his hands. He straps himself into the harness on the Athena Parthenos, carrying Hedge, while Reyna holds the ghosts off and shadow travels away just moments after Reyna grabs his hand.
Nico passes out after shadow traveling. While he is out, he dreams about his life in Venice, Bianca, and him in a mall in Washington, D.C., and Percy shielding him from Dr. Thorn. He is pulled to Hypnos' Cabin by the dreams of Clovis, who shows him that day's war meeting at Camp Half-Blood, which shows that the Greeks are cornered in by the Romans and preparing for the invasion. In the dream, he sees Chiron, Rachel Dare, Grover Underwood, and several campers: Clarisse La Rue, Jake Mason, Butch Walker, Connor Stoll, Malcolm Pace, and Will Solace. Will's blond hair and blue eyes remind Nico of Jason, but says the similarities stop there. He describes Will as a 'lanky cat stretched out in the sunshine' and says although he is relaxed and non-threatening, Nico knows Will is brave in battle. After telling Clovis to pass a message on to Thalia Grace, he is woken by Coach Hedge thirty-six hours after passing out. Hedge informs him that they overshot Spain and went to Portugal instead and that the Athena Parthenos was on top of a temple. Hedge then tells him a ghost is asking to talk to him. Nico goes to the ghost, who leads him to a church that is decorated on the inside with the bones of deceased monks. There he meets his father, who tells Nico that his quest is hard and he might not survive the trip. He also tells him that Orion and his pack is hunting Nico, Reyna, and Hedge and that one of the seven will die. Before Nico can ask more questions, Hades vanishes. He goes back to the temple and has lunch with his companions. Suddenly Lycaon and his pack surround them. He informs them that he is going to kill them for Orion; however, Orion wanted him to detain Nico. Nico summons bones from the ground to imprison the wolves momentarily while the three ran towards the Athena Parthenos. When the werewolf breaks free and attacks Nico, Nico stabs him in the chest with Reyna's silver knife, getting clawed in the process, and uses the shadow left by Lycaon to shadow travel away.
After Portugal, Nico shadow travels to a cruise ship in the middle of the Atlantic for a day, where he discarded his aviator's jacket due to the damage it took, and Reyna patched up his gashes. He then travels to San Juan, Puerto Rico, ten feet above a restaurant. After he goes to sleep, Reyna puts her backpack under his head. However, her hand passes through his head on her first attempt and lifts it the second. When Nico awakes to find Reyna gone and a note from the Hunters, he tore the note up in a fit of rage. Later he and Hedge put on new colorful tourist shirts -much to his annoyance- before joining the fight against Orion. Once the two meet up with Reyna and Thalia, Nico, Reyna, and Hedge retreat to continue their quest.
Two days later, the trio shadow travels to Buford, South Carolina. While Nico and Hedge go to the Zippy mart for supplies, Reyna stays behind to watch over camp. When the boys come back to base camp, Hedge goes to write letters while Nico and Reyna talk. She tells him about her father and family history. In return, Nico told her about his relationship with his father, and that cheered her up a little. Just then Bryce Lawrence shows up and summons British redcoat skeletons to apprehend Reyna and kill Nico and Hedge. He threatens to torture Hedge to death and taunts Reyna about her secret about her father. This infuriates Nico, whose temper explodes. He proceeds to unleash all his painful memories since falling into Tartarus on the others at the camp, revealing his secret in the process. As the temperature drops to freezing and the skeletons dissolve, Nico marches over to Bryce and opens a fissure beneath the other boy's feet, and as Bryce sinks into the ground, Nico turns him, body and all, into a ghost and sends him to the Underworld. After that he collapses, nearly fading away into a shadow because of overuse of his powers, and wakes up with Hedge and Reyna bandaging him. They had managed to save him through Hedge's sports medicine and nature magic. They tell him what happened with Bryce, and to his shock, they tell him that they still trust him. Moments later, a flock of Pegasi arrives to help them take the Athena Parthenos to Camp Half-Blood, led by Pegasus himself.
The flock flies Nico and his companions to Camp Half-Blood by the pre-dawn of August first. They land on a yacht, and Nico sends "some strong dreams" to the mortals below deck, much to Reyna's awe. Soon after, Michael Kahale, Leila from the Fourth Cohort, and Dakota from the Fifth Cohort come to arrest Reyna and bring in Nico to be executed as an enemy spy. Hedge attacks the son of Venus to little success, but then the people on the boat hear the voice of Octavian, saying he had come to see to the arrests himself. Seconds later Tyson, who presumably had imitated Octavian's voice, and Ella knock out the first cohort centurions. The other two centurions decide to help Reyna and declare their loyalty to her. They tell Reyna what their base camp is like, and she sends them to get their cohorts to leave Octavian, and Nico to sabotage the legion.
After they arrive at a private dock and haul Michael Kahale out of the boat, they wonder who will drive the SUV, and Nico volunteers, much to their shock and nerves. He then summons Jules-Albert to drive the SUV through Roman ranks. When they arrive they see that the legion is outnumbered by monsters. Dakota and Leila get out to get their cohorts to switch sides, while Nico goes to sabotage the siege weapons. When he shadow travels to Half-Blood Hill, he is startled by Will Solace, Lou Ellen, and Cecil, who are spying on the Romans. Will and Nico immediately start bickering, Nico being annoyed by Will ordering him to not use his Underworld powers. Nico also notes that Will doesn't back down from Nico in fear like others do, and seems annoyingly determined. While talking to Will, Nico remembers when he first arrived at Camp Half-Blood with Apollo years before, and Thalia Grace calling Apollo hot, but quickly shakes the 'random' memory. The four were successful in sabotaging half the weapons before being spotted. Octavian then comes out with the First Cohort. Nico states that he is helping both camps and that he will leave once the war is over. Will is upset by this and tells Nico that a lot of campers want to be his friend. Dakota and the Fifth Cohort arrive while the rest of the cohorts are surrounded by monsters. Moments later Camp Half-Blood is lead to battle by Clarisse La Rue, Grover Underwood, Tyson, and Chiron. They are all stunned by Will's whistle, and Nico speaks of peace as Reyna flies the Athena Parthenos into camp as a peace offering. Which works until Gaea awakes.
As the Seven arrive at camp, Nico is helping fight the monsters. During the battle, Will comes over to him and whispers "Octavian" in his ear before leading him to an onager, where Octavian is preparing to blast Gaea. Will and Nico try to talk him out of it, noticing that the Imperial Gold he's wearing seems to be attracted to the loaded projectile and is snagged, but he refuses to listen. Will continues to try and talk him out of it, but Nico tells him that some deaths cannot be prevented. Octavian then fires and gets dragged along with the shot. They witness Leo's sacrifice, but Nico senses that Leo's death was strange. He talks with Percy, Annabeth, Jason, Piper, Hazel, and Frank at the Big House, where Frank and Hazel explain Leo's plan tearfully. Chiron asks him to perform the final rites for the fallen demigods, and Nico agrees. He hadn't spoken to Will since the battle, thinking the son of Apollo would think Nico a monster for having let Octavian die. Later he sits by the campfire and listens as Chiron explains how the two camps have become friends, and that they can visit each other's camp. Then Reyna tells the two camps about Nico's part in saving the camps, brings him out of the shadows, and hugs him, and he tearfully returns it. The next morning, Jason knocks on Nico's door. For a second, Nico though he was Will Solace and was disappointed when he realized he wasn't, getting angry with himself for feeling that way. Jason and Nico go outside to talk. During this conversation, Nico tells Jason that he will stay at Camp Half-Blood. Nico is then called over by Will who angrily asks Nico where he was for the past few days, saying he would've enjoyed having Nico around to help out or just as a friendly face. He then tells him to stay in the infirmary for at least three days, which made Nico feel "like a hundred skeletal butterflies were resurrecting in his stomach". Nico then sees Percy and Annabeth and walks over. They tell him they will attend college and live in New Rome. Nico then tells Percy he had a crush on him and is now over him, earning him Percy's shock and a high-five from Annabeth before Nico goes back to Will.
==Between the Series==
Several days after the deaths of Gaea and Leo, a parchment scroll with a holographic message, sent from the resurrected Leo, came fluttering into Camp Half-Blood on the wind, with Nico being the one to keep it (in his jacket's pocket) after the other campers had finished re-listening to it. While extremely relieved after learning of Leo's survival (due to him having blamed himself for Leo's death and unable to forgive himself), Nico is also enraged at Leo for scaring him, so he looks at the scroll whenever he wants to get angry at Leo.
At some point during the ensuing months, Nico finally decides to come out and confess his feelings to Will Solace. He asks the satyrs to help him plan a picnic, but they misunderstood and create a picnic themed coming out party at the Dining Pavilion for the whole camp. Despite the misunderstanding, Nico comes out to the son of Apollo and, after Will reveals he feels the same about the son of Hades, the two begin dating. In doing so, he gave other LGBTQ+ campers the courage to come out as well.
In order to sit together with his new boyfriend during meals, Nico claims to Chiron that he somewhat loses control of his infernal powers while sitting alone at the Hades' Cabin table, and so he is therefore given permission to sit at the Apollo's Cabin's table instead, as Will produced a handy fake doctor's note, and Chiron decided it wasn't worth arguing about.
At one point he and Will accidentally shadow traveled to the largest Cheez Whiz factory in Venezuela.
By September, however, most of Nico's friends temporarily leave camp, with Percy and Annabeth returning to New York to spend their senior school year together, while Jason and Piper depart a month later (spending most of September searching for Leo), to spend their school year in Los Angeles (with Tristan McLean), also taking Gleeson Hedge, Mellie, and Chuck along with them. It can also be assumed that Nico is rarely visited by Hazel and Frank, as he describes them being busy "doing the Twelfth Legion thing" at Camp Jupiter.
==The Trials of Apollo==
===The Hidden Oracle===
Spoiler alert. Hit "Expand" if you want to continue anyways.
Nico meets Apollo, Will Solace, and Meg McCaffrey at the Big House. Nico donned a new outfit: A Ramones T-shirt that Apollo liked for music taste, black pants, and a leather jacket. Nico told the fallen god that he had a thick aura and a great possibility of death around him. Will told Nico that they needed another talk for people skills and apologized for his boyfriend's behavior, getting an eye roll and a "Can you not?" from Nico. Will asked what he preferred instead of boyfriend, suggesting "special guy" and "significant other", and Nico said significant annoyance. Meg noted that they fought a lot. After discussing problems at camp, Chiron ordered the two boys to get the other campers for dinner and to go together, using the buddy system. Will asked if Nico wanted to be his buddy, and Nico called him a dork. Apollo was supportive of his son's relationship with Nico. 
At dinner, Nico sat with Will, Apollo, Austin, and Kayla. Apollo thought Will and Nico were so cute together it looked desolate, reminding him of his old relationship with Hyacinthus. Nico explained to Apollo that he had a doctor's note to sit with Will at dinner and that Will was his doctor. Nico also told Apollo the whereabouts of the Seven and Gleeson Hedge. When Apollo asked about Leo, Nico said that if he saw him again, he'd kill him. Nico showed Apollo the scroll Leo sent and said he looked at it whenever he got angry, and how he hated being left in the dark because he didn’t know if he was safe or planning anything.
While Chiron talked about the Three-Legged Death Race, Nico chastised Will for staring at Paolo's arms, but Will said he was making sure they were working after surgery. Nico also told Apollo that Grover was in California with the Council of Cloven Elders. When Peaches came, Nico told Meg to stay out of the way, because he was dangerous. Nico bowed down respectively when Meg was claimed by Demeter.
The next day, at the Three-Legged Death Race, Will and Nico were partners, tied together. After Will said that he missed Grover and rested his arm on Nico's shoulder ("as if the Son of Hades were a convenient shelf", as Apollo put it), Nico pushed it off and said he'd settle for Coach Hedge, and to not talk about Grover so loudly, since Juniper was nearby. After the race, Nico helped a stressed-out Will reattach Paolo's leg and gave Will water, saying that was where he needed to be. Nico was angry about the missing campers and the grass withered around him. Will asked him if he wanted to set Valentina's arm, and Nico said it sounded gruesome, but did it.
Later, when Meg and Apollo went to find the Grove of Dodona, Nico gathered with Will, Malcolm, Paolo and Billie for a going away party. Nico gave Apollo ambrosia for Meg because he could sense that she had a chance of death, making Apollo shiver. Nico smirked when Paolo gave Apollo his bandanna and listened to what he said because he understood Brazilian Portuguese. Nico explained that it was Paolo’s good luck bandanna and that he believed it would make Apollo invincible.
When Apollo showed up to Camp at six in the morning, they took him to Apollo's Cabin to heal him. They wanted to search for Meg in the woods but Chiron wouldn't let them. When Apollo woke up and started talking to the flowers, Nico was concerned and asked Will if that was normal. Nico told Apollo that he and Will were worried, and put his hand on Will's shoulder. Apollo told Nico that Meg had until that night at the latest and went to get dressed, and Nico wanted to help him, saying that he could shadow travel him there, but Apollo told him to protect the Camp. Apollo told him that Nero and the other Roman emperors were alive and divine, and ran out of the room, leaving Nico in shock.
Later, Nico and Will were capsized in the middle of a canoe ride when the Colossus Neronis attacked. He and Will rushed to Apollo during the battle and chatted with him. When Apollo asked for his children to come with him, Nico went with them too, because he had a doctor's note. Nico then grabbed Will's hand and shadow traveled to steal Sherman's chariot, where he convinced Alice, Julia, and Sherman to get off so he could steal it. Austin said he hated it when Nico shadow-traveled. They landed the chariot near Apollo, with Nico half-conscious. Sherman was angry that Nico stole his chariot and screamed from the distance. Nico passed out in Will's arms and Will took him to get Gatorade. Nico was affected by the hay fever epidemic. Percy later mentioned that he almost lost Nico to the enemy.
Later, when Leo returned to camp with Festus and Calypso, Nico ordered a line from the snack bar to punch Leo, where Leo questioned if it was really necessary. When Calypso mentioned Albania, Nico said to not mention Albania. When the line was over, Leo asked Nico if he was done with the physical abuse, and Nico smiled and said that at Camp Jupiter, there were many people who wanted to punch him. Leo winced and asked where they can get lunch. Nico later prepared marshmallows for s'mores for the bonfire on femur bones.
===The Dark Prophecy===
Apollo mentioned Nico when seeing Marcus, the new second in command of Nero.
===The Tyrant's Tomb===
Hazel Levesque mentions Nico when thinking he could help cure Apollo’s scratch. Apollo mentions him when thinking his condition can not be cured with the combined efforts of him, Will, and Pranjal. He is also glad he is not at Camp Jupiter.
===The Tower of Nero===
Spoiler alert. Hit "Expand" if you want to continue anyways.
After sensing Jason's death, Nico starts to suffer from post traumatic stress disorder. Around the same time, he starts to hear voices calling his name from Tartarus. He talks to Will about it, and Will tells him to speak with Dionysus.
He and Will are on the porch of the Big House drinking lemonade when Apollo and Meg return to camp after six months. He asks about Jason's death and they silently confirm it. He stands in silent shock for a moment before saying "excuse me" in Italian and running away. Will says that he only slips into Italian when he's really upset. The following morning, Apollo asks Will why Nico isn't at the table and Will points to the head table, where Nico is having breakfast with Dionysus. Will explains Nico's spiral after Jason's death and his PTSD, and Apollo notes that Will seems very concerned about his boyfriend. Will talks about the voice Nico has been hearing from Tartarus and says he is working with Dionysus, God of Madness, to figure out what is real and what isn't. Will also says that if the voice is real, he and Nico plan to go into Tartarus together. Dionysus calls Apollo and Will over to the head table. Meg joins them and they try and make meaning of the prophecy. Will puts an apple on Nico's plate and tells him to eat something, but the apple responds to Nico's emotions and starts to wither, and Nico leans into Will for comfort. It is revealed that Will didn't tell Nico about the line of the prophecy mentioning a son of Hades, likely because he didn't want Nico to be put in danger, which upset Nico. When they mention the part about him being "the cavern runner's friend", Nico knows what it means and gets supplies to meet up with them, with Will reluctantly helping. The following morning he and Will go with Apollo and Meg to Brooklyn.
Argus drops them off a block away from Rachel's house and they walk the rest of the way. When they arrive, Rachel hurries them in, as the cows are watching. She takes them to her room. When Nico complements her paintings, she playfully pushes him away and warns him about getting color on his clothes. Rachel explains that three cattle cars full of neglected livestock arrived at her house on a previous day, and when she contacted the authorities, they denied seeing anything. They then change the topic to Nero. She confirms that the fasces is on a heavily fortified floor in the center of the tower with the holding cells. Nico asks Meg why Luguselwa is having them destroy it if she is unable to. After Rachel talks about an underground filtration system that could pump Greek Fire into the city's sewer system, he reveals that his "friends" are Troglodytes, expert tunnelers who can get in and sabotage the system without Nero ever knowing. Will is against it, but Nico mentions this is their part of the quest. Soon after, Rachel utters a prophecy in Python's voice and passes out just as the cattle break into the property. They escape just as the mansion collapses and make their way to a construction site with a fifty-foot pit. They jump onto a nearby crane just as some of the cattle, which Apollo realizes are the troglodytes' natural enemy, Tauri Sylvestres, fall into the pit and choke to death on their anger. As the others question if they can fight them off or if Nero is coming for them, he sees a cluster of shadows he can use to get them away. When they climb down he says he can only take two with him at a time and, as one of the bulls slides into the pit, Apollo and Meg volunteer Rachel and Will. He takes the two and returns for Apollo and Meg.
He brings them to an underground cavern and promptly falls asleep. Will props a travel pillow under his head and explains that he needs about half an hour to recover from the shadow traveling. When he regains consciousness, he is confused, and Will gently tells him he's with friends. He leads the others to the troglodytes and tells them not to touch their weapons. He asks Will to 'do his thing', which turned out to be the power to glow with golden light. Nico happily calls will his "glow-in-the-dark boyfriend". When he announces their presence, the troglodytes surround them. Screech-Bling, their leader, asks Nico if they are sacrifices. He says they are not and offers him a skink, a rare treat for his people, and they are brought to their camp. He and Will sit together and Will expresses his concern about their situation, to which Nico replies with word of assurance. He then speaks with Screech-Bling as dinner is being prepared. As they eat they are given hats, with the son of Hades receiving a top hat. Apollo and Rachel help him make a case to help save the city above. The troglodytes agree but become angered that the forest bulls followed them. During the chaos, Nico, Will, and Rachel are separated from Apollo and Meg.
Nico and the troglodytes sabotage the filtration system. He makes his way to the main levels of Nero’s tower and saves Apollo by killing the guy about to kill the god. He informs Apollo that the building is under attack and that the others are off fighting. He walks the mortal god through a confidence room where mortals are fighting the troglodytes. They meet up with the forces of Camp Half-Blood. He passes Apollo over to Kayla as he goes to look for Will. At some point before he's seen by Apollo again, he either finds a dead forest bull or kills it himself, taking control of the bull's skeleton. At Rachel's urging, he goes to the throne room. He uses the bull to break down the doors and attack Nero, but Nero's forces are able to overpower it. He goes to Apollo and Meg and informs them the troglodytes are still searching for the gas as he takes out two Cynocephali. As Nero searches for the right remote to trigger the gas, Nico takes on numerous Germani before charging at Nero himself. However, the god-emperor catches his sword and throws it aside before slapping Nico away and knocking him unconscious. Right after, Will, Rachel, Screech-Bling, and Lu arrive with the fasces. Will screams that no one hits his boyfriend and no on kills his dad. He helps Nico up, yelling at the enemies to move so he can take him to the side safely. He heals Nico as Apollo and Nero fight over the faces, and both see the emperor disintegrate. After Nero's death, Nico and Will help Apollo recover and prepare for his fight with Python. When Apollo and Will send Nico to get the ukulele as well as the bow and arrow, he questions if they really hate Python so much as to subject him to that. Will simply raises an eyebrow and Nico runs off to comply. He gives Apollo a reassuring look as the former god leaves to take on Python.
Two weeks later, after the campfire, Apollo, having regained his full divinity, sits with Nico, Will, and Rachel and watches the embers burn down. The two boys sit comfortably next to each other- Will's arm is around Nico's shoulders and Nico is twirling a burnt marshmallow on a stick. Rachel confirms that Python's death restored her powers. She discusses taking a gap year in Paris to study art, but she promises to be back the next summer to continue her work as the Oracle of Delphi. Nico promises that if they ever need her, he can Shadow Travel Rachel to camp. Will comments that he'd love to think that Nico is planning a date night in Paris, but knows that he's really hoping for prophetic guidance about Tartarus. Nico simply calls it unfinished business. Apollo remembers Nico telling him about his compulsion to explore the depths of Tartarus and a voice calling out to him for help. Apollo questions if it could be Jason. Nico admits he'd considered that, along with trying to bring Jason back, but he's sure that this is not about him. Nico has a sense that Jason made his choice. If Nico tried to bring Jason back, he wouldn't be honoring Jason's sacrifice. Resurrecting Jason would not be like resurrecting Hazel, who needed to come back. Nico senses that Jason is in a better place now, though Apollo can't confirm if it is Elysium or rebirth. Nico explains that the first time he was in Tartarus, someone helped him and later helped Percy and Annabeth, but he got left down there and Nico can't stop thinking about him. Will asks if he should be jealous until Nico states that it's a Titan, Iapetus, surprising Apollo. Nico calls it a long story and insists that Iapetus isn't a bad guy. Nico feels like he should look for Iapetus and try to find out what happened to him, in case his friend needs his help. Though Hades has expressly forbidden traveling to Tartarus ever again, Nico plans to use the troglodytes who can tunnel even to Tartarus and can get him and Will in and out safely. Apollo, though he dislikes the idea, admits that though he wishes he could help them, he can't as it is outside his jurisdiction. Will takes Nico's hand and promises that it's fine and Apollo has already done his part. Just as Will asserts that they will succeed with or without a prophecy, Rachel suddenly tips over. Will and Nico catch her, and she issues a prophecy that only they can hear. Nico asks if Apollo heard the prophecy. Apollo admits that he didn't and probably shouldn't. Will agrees, stating that what Rachel told them doesn't sound good.
==Un Natale Mezzosangue==
Nico takes Percy to Florence after the son of Poseidon struggles with finding a gift for Annabeth. The son of Hades takes him to store owned by Charu, the last of the Etruscan gods. After asking questions about Annabeth, he gives the son of Poseidon and bracelet of keys and asks him to explain the meaning of Christmas. After Percy explains the universal meaning of friendship and family behind the holiday, he is given the gift and the demigods leave. 
==The Sun and the Star: A Nico di Angelo Adventure==
To see this text, hit the "Expand" link to the right.
Two months after stopping Triumvirate Holdings, as the summer session ends, Nico and Will walk with Austin and Kayla to Half-Blood Hill. As they walk, the son of Hades is asked which Star Wars character he would date and answers Darth Vader. When they arrive, Austin and Kayla are nervous about their travel arrangements as Chiron calls the Gray Sisters' Taxi. As it arrives, Austin reveals his mother moved to Harlem after he got into school there and Kayla is going back to Toronto. Will says he is staying at camp as his mother is touring for her new album. As Will's siblings leaves, he and Nico- the only demigods currently at camp- walk to the Dining Pavilion. As they walk, the son of Hades thinks about the prophecy he heard a few weeks ago and thinks of the ghosts he will eventually meet. When they arrive, they see Chiron and Dionysus talking.
After dinner, Nico rests in his cabin thinking about Iapetus and tries to to fall asleep. He fails and hears a voice as he drifts into sleep. In his dream, Nico hears his mother telling him to listen in Italian. Soon Nico finds himself in a room at the Lotus Hotel and Casino and sees Bianca sleeping in the other bed in her hunter outfit. Nico gets out of bed and looks in a mirror to find his mouth missing and looks over to find his sister missing. Nico then finds himself on the Williamsburg Bridge during the Battle of Manhattan and sees Kronos. He backs away but Percy, Annabeth, and Michael Yew push him towards the titan and Michael tells him to listen or he will meet the same fate as him. Nico then appears in the jar Ephialtes and Otis kept him in and the lid open to reveal Percy trying to pull Nico out. The son of Poseidon vanishes reapears with crying eyes. He tells Nico he made a mistake and the son of Hades must fix it. He next finds himself in Croatia as Favonius tells him he has to meet with someone and he soon hears Cupid. Cupid, while invisible, tells Nico to look at him. Nico says he cannot and is pinned against a column. Cupid appears in the form of Will and tells Nico he must tell the truth when the time comes. As Nico is able to be eaten, he wakes up and kicks Will, who came over after hearing the son of Hades scream from his cabin. As Will hugs him, Chiron appears with Rachel Elizabeth Dare in tow, saying she needs to tell him something. Rachel recites the prophecy she emitted two weeks after Nero's down fall and says that is the twelfth time she recited it. Chiron is unnerved by revelation as Dionysus walks in with a bowl of popcorn. Nico tells them everything about insists that he must go to Tartarus to get Iapetus back. Chiron and Dionysus are hesitant as they question if Bob has truly reformed or if it is a trap. As Dionysus mentions that Hades closed off the Underworld to the living, Nico says they will be in and out before his father notices. Chiron states he will need three to go on a quest and Nico insists he and Will go as Percy and Annabeth managed the previous summer. They question Nico leaving something of equal value behind and he fears Will might sacrifice himself. The son of Apollo says he will not make sure Nico does not either. Chiron reluctantly agrees to authorize the quest as Nico questions if it is the right move.
In the morning, Chiron helps Nico and Will pack their bags and has them take Ambrosia and Nectar. After taking a mortal cab to the train station, they ride the rails to Manhattan. Along the way, Will tells Nico of the time he and his mother came to New York City and says the first time he was in the city his satyr found him and brought him to Camp Half-Blood. As they reach the penultimate train stop, Nico decides to take a detour. When the train reaches Penn Station, they head out to go up town. As they head to the subway, a tourist spills her drink on Will. They make their way to the subway and, after several delays, reach the Jackson Apartment and are greeted by Sally Jackson and Estelle Blofis. After explaining their quest, and stating they only want advice from Percy, Sally says Percy should have a free period at the moment and takes them to him room where they use a humidifier and a lamp to contact Percy. After sending an Iris Message, they speak to Percy and Annabeth. After Sally leaves the room, Nico and Will explain their quest and Percy and Annabeth express their guilt that they forgot about Bob. After the son of Poseidon and daughter of Athena fail to talk them out of it, they tell the sons of Hades and Apollo that their best chance at surviving Tartarus is to stick together. They end the call and, after saying goodbye to Sally, continue on.
Nico and Will head to the southern most point of Central Park and stop at a pile of rocks. Nico explains that these are the Door of Orpheus and Will needs to sing to open them. After Nico explains he will ask the Troglodytes for help as a favor for finding them a new home in the Underworld, Will expresses criticism that they would help the people who destroyed their home in the first place. The son of Apollo reluctantly agrees to sing and the doors open. Before the doors close, Nico thinks he saw something but brushes it aside. As they descend the stars, Will expresses his concern as Nico comforts him. Eventually they reach the Underworld and upon welcoming Will, he asks the son of Hades what he means. Soon the scene changes and Nico realizes they are still on the stairs, much to his confusion. The boys continue on and they both see a light. However they soon find themselves back in Central Park at night and Will collapses to his knees in exhaustion. He helps Will up and they open the Door of Orpheus again. This time, Will glows and they reach the Underworld. However, the son of Apollo collapses in exhaustion and struggles to stay awake. Nico tries to wake him to little success and falls asleep soon after. Nico wakes up and sees a mass of dark tendrils nearby, hovering over Will. Nico attacks the creature and it takes a more humanoid form. The creature introduces themself as Epiales, a demon who has been watching Nico for some time and Nico realizes they trapped him and Will in a dream. After stating they do not work for Hades, Nico searches for bones to utilize as a weapon. However upon finding bones, Epiales wraps their tendrils around Nico's wrist and berates him for thinking they are that naïve. Soon Will wakes up and Epiales puts them both back to sleep. Nico dreams of the day he learned Bianca died. As he walks into the Big House, he sees Chiron and the councilors looking at him sadly. However when Chiron speaks in Epiales's voice, the son of Hades regains control and threatens Epiales. After accusing them of tormented his dreams for months and the demon only admits that they have been manipulating his dreams since the stairs. Nico wakes up and attacks the demon, pinning them down and summons skeletons. However, Epiales disintegrates the skeletons and creates an illusion of Dr. Thorn. Soon Will wakes up and, realizing everything he experienced was in dreams, blasts the demon with light upon seeing Nico in danger. Epiales looks at Will in shock and says the boys will meet their mother soon enough. Will hesitates in finishing the demon off, but does so after they try to attack Nico. After Nico thanks him, the son of Apollo passes out.
He watches over Will as the son of Apollo rests. As he does, Nico thinks on the fact that he has a boyfriend due to his decades in the Lotus Hotel and questions what would of happened if he was never put in the hotel in the first place. When Will wakes up, he explains how he has been training with his control over light. The two set out and Will tells Nico his dream Epiales gave him. When they reach the River Styx, Nico points out a path past a waterfall to avoid Hades and Will puts a sweatshirt to cover as much skin as possible. The boys make it past the waterfall and Nico calls out to the troglodytes. Screech-Bling welcomes the pair and takes them to his people's new home. The demigods are impressed by what they did and are surprised the troglodytes have rerouted the River Styx and Screech-Bling says his kind have no ill effect from the water. He takes Nico and Will to the communal dining area and Click-Wrong gives the boys human food. They enjoy it and he reveals it is tomato soup with lizard and shoe laces. Nico laughs while Will shutters in disgust. Soon the troglodytes start sniffing the demigods and they reveal they have been smelling the same thing for the past few weeks. After thinking, Nico gets an idea about who is sending him the dreams and the son of Hades asks Screech-Bling to call his council. Screech-Bling leaves and the demigods follow him. Once the council is gathered and introduce themselves- Howl-Smith, Clack-Jones, Shriek-Vibes, and Hiss-Majesty- Nico reveals that he thinks they are going to face Nyx. The troglodytes are shocked as Will questions who Nyx is. After Nico explains, she is a being older then the gods and titans, the son of Hades reveals that he met her before, causing an uproar. Will is stunned and Nico reveals it was too hard for him to share and told no one. After saying he needs to tell it now, the son of Hades reveals what happened the last time he was in Tartarus. 
After he finishes his story, Will and the troglodytes stare at him in shock. After retelling the story, Nico wells up and cries into Will's shoulder. After Nico calms down, the troglodytes express their concern that Nyx is after them in an attempt to get to Nico. The sons of Hades and Apollo theorize that Bob has been trying to get help from Nico as Nyx is trying to force him to be his old self as she thinks people can only be one thing for their life and cannot accept that they can change. The troglodytes agree to house Nico and Will until mushroom-glow, their equivalent of morning. Will expresses his displeasure with the Underworld, hurting Nico. After they are taken to the nursery, they fall asleep. Nico dreams that he is before a covert and Nyx takes the form of Bianca. He tries to ignore her, but the goddess fires an arrow at his chest, causing him pain. She says she will be waiting for him as he wakes up. He walks around the nursery and thinks of that day’s events and vows to keep Will safe. He is given broth for breakfast and gives a cup to Will when he wakes up. Will is hesitant until Nico says the troglodytes diet is mostly similar to a human's. Screech-Bling and Hiss-Majesty arrive and take them to a tunnel. Will gives Hiss-Majesty his sun globe and they crawl through. Soon Will starts to hum a song his mother wrote about her time with his dad and son of Apollo starts to glow. Nico suggests he conserve his energy. As the four near the end of the tunnel, Screech-Bling says they have one more obstacle. 
They emerge from the tunnel and Will is exhausted, Nico rests him on a boulder as Screech-Bling and Hiss-Majesty hunt for lizards. As Will rests, Nico looks into the distance at his father’s palace and realizes he is unfamiliar with this part of the Underworld. Will asks Nico if Hades was always in Nico's life, Nico says his father was and Will says he only learned what he was at ten and only met Apollo years later. Will expresses his desire to meet Hades the next time they are in the Underworld. Soon the troglodytes return and say they must pass a farm. Nico vaguely remembers his father telling him about a farm but does not recall the details. Will is shocked that a farm could function in the Underworld and Nico is hurt by his comment. Soon they find the farm and spot a bull man with red skin. He spots the four and runs over to them, saying they will not get away. The bull man greets them and Nico introduces him as Menoetes, a demon assigned to tend to Hades's cattle. After inadvertently revealing their quest, Menoetes informs them he must tell Hades they are in the Underworld. However, Menoetes agrees to keep their presence a secret if they go on a quest for him. Nico asks what he wants, and Menoetes says he wants them to sneak into Persephone's Garden to steal fruit for his boyfriend Geryon. Nico is shocked that he is dating the giant who nearly sold him to the titans but Menoetes insists he changed and wants to do something special for him. Reluctantly, Nico agrees to the quest and Menoetes calls forth donkeys for the demigods to ride on. Screech-Bling and Hiss-Majesty stay on the farm as the demigods head out. 
When they reach Hades' Palace, the boys dismount and Will is disturbed by the images of death on the gates. Nico leads the pair to a hidden gate and opens it with a bone from his pocket. They sneak inside and the son of Apollo is captivated by all the plants and the sight of Persephone. Nico tells him to stay vigilant as the Queen of the Underworld moves to the far side of the garden. The boys wonder if they were set up, but Will thinks Menoetes is genuine in wanting to surprise his boyfriend. Nico takes Will to the center of the garden and they take pomegranates. While he is unable to touch them, Will easily picks three of them. They boys sneak back to the gate and, as he scouts ahead, Persephone finds Will. However, Nico is unaware of this as his stepmother freezes him in place and speaks with Will. The son of Hades has no recollection of the incident upon being unfrozen and the boys return to Meneotes.
Back at the farm, Nico and Will see Hiss-Majesty joyfully herding cattle. When they arrive and present Menoetes with the pomegranates, the bull man eats one and explains he is happy where he is. As Will recounts their quest to the troglodytes, Menoetes tells Nico that many residents of the Underworld -including himself- have heard Bob’s scream. The bull man recounts a sighting one of his workers said upon regenerating that Nyx is forcing Bob to stay in a regeneration blister until he becomes Iapetus again. The demigods are angered as they learn it is agonizing to stay in one for too long. Menoetes tells Nico and Will that once they enter Tartarus, they should emerge close to a swamp where the hut of Damasen is located and that Bob is not far from there. Screech-Bling and Hiss-Majesty tell Nico and Will they must keep going. The bull man waves goodbye as they walk. As they walk along a slope, Will becomes sluggish. They spot a pair of drakons and try to avoid them, but Will falls down the side of the slope and Nico shouts, attracting the drakons. Nico goes over to his boyfriend as the troglodytes distract the drakons. Nico inspects Will, who is unconscious, as Screech-Bling comes over having just narrowly avoided the drakon's flames. After Screech-Bling offers to watch over Will, the son of Hades attacks the drakons. At first his sword bounces off, but his second blow severs one of the drakon's legs. It disintegrates as the other one runs off. After tending to the son of Apollo’s injuries. When Will can stand, they move out. As they walk, Will slowly heals, but his wounds soon open along with a fresh gash in his torso. Soon they reach the River Acheron, where souls who are deemed to evil for the fields of punishment are bathed to cleanse them of their past actions. The demigods, believing they have to win in it, are hesitant and start to argue. Once the fighting dies down, Screech-Blings says they can take a boat and points out a woman by a hut. The troglodytes turn back, with Hiss-Majesty saying they will return to Menoetes's farm. The say their goodbyes and Nico and Will head towards the hut.
As they reach the hut, the woman -a nymph- greets the two and introduces herself as Gorgyra. Both Nico and Will, having never heard of her- look at each other in confusion and Gorgyra is not surprised. She explains that her husband, Acheron merged with the river one day and since then, she has been weaving the souls of the depressed and remorseful into her dress. Nico hears the voices of the souls and tears up. Soon the nymphs pulls a thread of soul from the sons of Hades and Apollo and they are shocked and disturbed by what they hear. She says they can use her canoe to cross into Tartarus, as it will allow them to survive the trip but still experience the effects of the river. When the boys ask what the catch is, the nymph says she wants them to tell her their story. Once they catch up to the present, Nico and Will tell Gorgyra about the gifts they exchanged after the Battle of Nero's Tower. Will gave Nico a bronze coin with a replica of Will's stylized sun tattoo on one side and the Helm of Darkness one the other, and Nico gave Will his skull ring. Gorgyra is impressed by their story and feels sympathy for the pain they felt, but says they need the pain to grow as people. The demigods board the canoe and set sail, hoping for the best. As Nico and Will set out, they hear the souls of the Acheron shouting at them, telling them they are vial for all their past actions. Nico and Will do what they can to tone it out, with the son of Hades being more successful then the son of Apollo, as they fall into Tartarus. As they fall, they feel like they are falling for days. Nico and Will see only darkness and hears the agonizing screams from the river. Soon they see clouds that Nico realizes is blood. When the ground comes into view, Will tells Nico he believes in him and the son of Hades summons countless bones to create a ramp to guide them to the ground. When they stop, Will laughs and compliments Nico on his quick thinking and the son of Hades welcomes the son of Apollo to Tartarus. Nico passes out soon after and as he is out cold, Will is abducted by a flock of Stymphalian Birds.
Nico wakes up under the boat to find a satyr like creature sniffing him. Nico jolts up and realizes Will is missing. The satyr asks him if he has seen a child and claims to smell the child on Nico. Nico says he has not and asks the creature, who introduces himself as a Lamian Centaur named Amphithemis, if he has seen Will. Amphithemis says he has not and continues to look for the child. After Amphithemis asks if Nico is a child of Zeus or Hera, he says he is a son of Hades and the two agree to help each other. Amphithemis sniffs Nico and they cross the Acheron, albeit reluctantly on Nico's part. After crossing, Amphithemis forgets who Nico is and asks about a child. Nico is confused and is stunned when Amphithemis reveals he was tasked with looking after Dionysus. Nico wades back through the river of pain and Amphithemis follows him. The son of Hades collapses in despair as Amphithemis tries to help him up. However, their hands pass through one another and Nico pulls his away in shock. Amphithemis gets angry and his eyes glow red, causing the son of Hades to realize he died long ago and is now a Mania. Nico tries to fend off Amphithemis but fails as he lacks any Imperial Gold. Thankfully most of the lamian centaur’s attacks phase through the son of Hades, however his left cheek is slashed in the tussle. Soon Nico sees Will and runs after him within Amphithemis on his tail. When he arrives, he sees a saber tooth tiger attacking a pack of Cynocephali and Will says he found Small Bob and the son of Hades introduces Amphithemis as a mania looking for Dionysus. After seeing Small Bob injured, Will says the dog men have the child and Amphithemis attacks them as the demigods and Small Bob run. When they get a good distance away, Nico berates Will as he was planning on helping Amphithemis pass on and chastises the son of Apollo for leaving him alone. Soon they fight and Will breaks down in tears and apologizes. He patches up Nico to the best of his ability but suspects Nico will have light scarring on his cheek. They head back to the canoe.
Will rests as Nico wonders if meeting Amphithemis was orchestrated by Nyx. When Will wakes up, he apologizes for leaving Nico and the son of Hades forgives him. They then try to figure out which direction to go as Will downs the last of their one of two canteens of nectar. The two notice Small Bob tying to push the canoe back into the river and they theorize they will reach the hut if they sail down the river. Will and Small Bob jump in as Nico pushes the canoe and, ignoring the voices of the souls, jumps in and the three set sail.
As they sail down the Acheron, Will falls asleep as Nico inspects their surroundings. As they pass a volcano, Nico starts to see the flesh that composes Tartarus. When the river goes through a mountain pass, Nico hears something and thinks they are being followed, but does not shift his gaze for fear of an ambush from the sides. As they exit the mountain pass, they end up in the stomach and Will wakes up. The boys cough as they realize they are being digested. Small Bob meows and Will notices mangrove trees and realizes they are in the swamp. The son of Apollo jumps out and wades through the river of pain to beach the canoe. Once a shore, Nico gets off and Will apologizes for not seeing the beauty of the Underworld. Soon they see seven Cynocephali and Nico summons the dead to fight them. However, a skeletal creature forms and attacks the dog men. The boys and Small Bob try to flee, but a second created appears in front of them. As the first monster finishes off the Cynocephali, Nico attacks the second and it calls out in pain before the first asks why he attacked them. The boys look on, confuses as the monsters introduce themselves as Carl and Bartholomew, a pair of Aetera. The aetera beg the demigods to kill them so that they can collect more bones and threaten to eat them when they refuse. Small Bob kills the aetera, much to their joys, and Nico and Will vow to keep this interaction to themselves. They trudge through the swamp for hours and Nico helps Will stand. Will says he fells himself fading as Nico talks about their past experiences and his life before meeting Percy. When Will reveals he is scared Nico will leave him behind to save Bob, the son of Hades swears on the Styx and the two demigods admit their love for each other. Soon they reach the hut and Nico calls out for Damasen. The son of Hades searches the hut and is shocked that no one is inside. As they wonder why Damasen has not regenerated since the Battle For Control of the Doors of Death, the two desire to shelter at the hut. They start a fire on some bones and Will is able to feel some sense of relief. Nico soon falls asleep and dreams he is watching a parade in Venice with his mother. However, when he addresses Bianca, he notices she is not there. His mother vanishes and a voice says he does not deserve their love. Nico wakes up to find Will next to him and Nico decides he should be more open with his boyfriend before falling back asleep. Nico wakes up and walks outside, Will joins him soon after and, after Nico fails to convince Will to rest more, the demigods head out. As they walk, Will hums a sing his mother wrote and asks Nico about his mother. The son of Hades says he remembers few things before his mother’s death and thinks of them as someone else’s, which he says is a coping mechanism used by those dealing with post traumatic stress. As they trudge on, Will starts to weaken and Nico takes out their last piece of ambrosia. Will tells him to save it for when they really need it. Soon they reach a wall of darkness that only Nico can see, remembering it from his first trip to Tartarus, Nico realizes they are close. He urges Will, who does not believe there is anything in front of them, to trust him and they enter. Soon Will sees what Nico sees and Nico almost falls into an invisible abyss, but Will catches him. Soon they find Bob.
Nico and Will go over to the pod and sees Bob shift from Iapetus to Bob and back again. Nico apologizes to Bob for taking so long and Bob says he was worried he could not hear him, however Bob becomes confused when Nico mentions a prophecy. Bob says it is not only Nyx who is doing this to him. Nico tries to slice open the pod and fails as Will fails to open the pod with sound. Bob says they must do it together and they demigods break the pod open. The boys and Small Bob hug Bob until they notice Nyx is behind them. The goddess unfolds her wings to reveal an army consisting of Cynocephali , Telekhines, Pit Scorpions, and dark pegesai, as well as Nemesis and Hypnos and Dr. Thorn. As Nyx starts to talk about tourism to her realm increasing, Nemesis and Hypnos silently criticize their mother's optimism for tourism as Nico demands Nyx let him and his companions go. Dr. Thorn goes to attack, but Nyx traps him in a vortex of darkness. A fight breaks out and Nico and his companions manage to hold off Nyx's forces with Will managing to hurt one of Nyx's wings. Soon Will goes limp and Nico rushes over to Will. Nyx subdues Bob as Nico realizes she will do anything to keep them in her domain. Nico urges Will to eat their last piece of ambrosia, but the son of Apollo refuses as the Mansion of Night appears and Will starts to lose what is left of his mental strength. Soon Bob breaks free and him and Small Bob attack Nyx as her children and minions watch. Soon the Mansion of Night catches on fire and Bob and Small Bob run over to the demigods, they pick up Will and leave Nyx's realm. Upon exiting, they find themselves by the River Phlegethon and the River Cocytus, causing the group to realize Nyx's realm moves around. When the goddess of night appears before them, she accuses them of arson, but they pin the blame on her children as Nemesis, Hypnos, and Epiales appear from behind. Nyx ignores her children's pleas to stop as Nico, Will, and Bob say they have changed and so can Nyx. Nyx ignores their words as she pushes Nico to reveal a detail he left out about telling the truth when the time comes and that if Nyx and her children fail to stop Nyx, Nico's children will. The four look at Nyx in confusion and the goddess calls forth over a dozen shadowy figures and claims they are the son of Hades's offspring.
Will questions what Nyx means and Bob offers to destroy the figures, but Nico stops him and goes over to the creatures and realizes they are Cacodemons, beings Nyx creates out of negative emotions. The goddess introduces each one to Nico as his worst memories appear before him. Nyx takes this as proof that Nico is meant to be guided by trauma his entire life and Nico attacks the goddess and summons the dead for back up as Bob and Will join in. The cacodemons attack Will and, after realizing they must obey their maker and who they are made from, he commands them to stop and they obey with the commands from Nyx being cancelled out. Nyx commands her children to attack, but they refuse and subdue the goddess of night as Nico tells Nyx she helped him over come his trauma and, after remembering the prophecy, releases the cacodemons to be their own beings and fulfills the prophecy. Bob picks up Will and Nico and jumps into the combined rivers, shielding the demigods from the effects. When they make it ashore, Nemesis appears and tells them she will do what she can to increase their chances of getting out and tells them to never return. When the canoe arrives, they sail the river of pain and see Nyx transform into a black hole. Nico and Will start to panic, but Bob tells them they are safe and points out that the river of pain spins silent. They watch as Nyx touches the Acheron and her skin burns. Nico realizes that since Nyx is nothing but pain and agony, the river rejects her. The group sees a hoard of cacodemons are running along the river and Nico realizes they want to come with them. The son of Hades tells Bob to stop so they could board despite Will's hesitation. As the cacodemons board the canoe. Nico starts to cry at the thought that the quest might finally be over and falls asleep. He wakes up as Will apologizes for his behavior forgives him and the two kiss as Bob calls them his sun and star and Nico falls back asleep.
Nico dreams he is back at the Lotus Hotel and Casino and he hears a voice. Thinking it is Nyx, he hides under the covers, but then he listens again and realizes he knows that voice. The son of Hades looks out from under the covers and sees Bianca di Angelo. Thinking it is a trick, Nico refuses to believe it is his sister. Soon he sees another person in a chair and realizes it is his mother. They tell Nico they have been granted permission to speak with him as a reward for completing his quest. Nico refuses to believe them until Hades appears. His father tells him he sent the prophecy and is proud that he saved Bob. Hades decides to grant Nico a wish and will fulfill it if it is possible. Nico wishes for Amphithemis to finally find peace and Hades agrees. The King of the Underworld tells Nico to find happiness for himself and to break the tradition of his children leading miserable lives. Hades leaves and Nico tells his mother and sister goodbye and that he misses them. They vanish and he wakes up. Bob tells him to go back to sleep as he is taking them to the land of the living his own way. Nico looks over to find the son of Apollo cuddling up with the cacodemons before falling back asleep. 
When Nico wakes up, he realizes it is morning on the Long Island Sound and they are heading towards camp. Nico is happy to see Peleus as they sail down a river through Camp Half-Blood Forest and end up in the Canoe Lake. They see Chiron at the dock and Nico jumps over board and swims to shore before hugging Chiron. The centaur explains that they have been gone a week as Bob helps Will out of the canoe. Chiron is shocked at the sight of the cacodemons and Nico reassures him they are harmless. Bob desires to head west to find himself as he rejects the demigod’s and Chiron's offers to stay at camp. As the reformed titan walks into the forest, Chiron offers the demigods breakfast and they should to the Dining Pavilion. When they arrive, Dionysus greets them and tithe sons of Hades and Apollo takes turns recounting the quest. By the end of it, Dionysus is happy with the outcome and intrigued by the cacodemons. Soon Nico goes back to his cabin to call Piper McLean. After sending an Iris Message, he is surprised to find Piper with a girl. Nico tells them about his quest and- after mentioning Jason- the girl, Shel, leaves the room. They talk about their shared grief and how Piper has been discovering her sexuality since the son of Jupiter's death. They say their goodbyes as the daughter of Aphrodite goes on a hike and the son of Hades goes to sleep. Nico wakes up and goes to the Apollo Cabin to find Will talking with Austin and Kayla via Iris-Message. They ask if the son of Hades is okay and they hang up. Nico and Will talk about how their experience in Tartarus brought certain aspects of their relationship to life. Will again apologizes for wanting to change Nico and Nico accepts it. As they lay side by side, the cacodemons enter and cuddle up with them. Once they are settled, Nico eagerly awaits what the future holds for him.
==Appearance==
Nico has black hair that always looks like he just got out of bed (messy and shaggy) and olive skin. By The Battle of the Labyrinth, his skin has paled to white, and he takes to wearing black clothing with skeletal designs, a Stygian Iron sword and a silver skull ring (by the end of the book). By the time he meets Hazel Levesque, she describes his fingers as ghostly white, like their father's. Percy stated that Nico has his mother's eyes, but it has also been said that they have the wild glint of a madman in them, too, just like his father. According to Percy, Nico's hands are "as cold as ice." 
By the end of The Battle of the Labyrinth, he has a silver skull ring which was Bianca's last gift to him and is said to belong to his father (as stated by Hazel). He also has a Stygian Iron sword always by his side in his chain belt. He is also mentioned on several occasions wearing an aviator's jacket, most likely because he was originally from WWII. Nico wears a black trench coat when he attempts to bring back Bianca, as shown in one of Hazel's blackouts. In The Last Olympian, Nico wears black battle armor with a skull-shaped helmet. In The Son of Neptune, Nico is seen wearing a black toga when Percy goes to talk to the senators (the reason being that togas are only worn on special occasions, like meetings). In The Mark of Athena, Nico appears weaker, thinner, and even paler than usual, while his eyes are described as "looking like shattered glass," due to his ineffable experience in Tartarus.
Days later, in The House of Hades, Nico has begun to recover and regain his strength, but is still described as "painfully thin," with his black shirt and jeans hanging loosely from his "skeletal frame." His dark hair is longer and frames his face. However, the area around his sunken eyes is very dark, while his complexion is even paler than before," a sickly greenish-white, like the color of tree sap." Being a demigod from another era, Nico radiates "a kind of old energy - a melancholy that came from knowing he didn't belong in the modern world." Nico is also the only one whose skin doesn't get tanned in the hot northern African sun, and if anything, looked even paler than before, according to Jason.
Jason comments that since getting out of Tartarus, Nico "had slept little and eaten even less." Seeing Nico casually eat a grape, he thinks that that will be his food for the day. Later, Jason is surprised that Nico actually has visible muscles when he takes off his jacket. According to Hazel, when upset, Nico's face would become "as dark as Tartarus." When Jason infuriates him, the ground opens up and Nico "glows with ghostly light." When Bryce infuriates him, the temperature around Nico drops to freezing, turning the ground around him white with frost. Several demigods, including Leo, Frank, and even Jason all admit to being afraid of the son of Hades.
In The Blood of Olympus, due to the stress of having to shadow-travel vast distances every day, Nico's skin gains a bluish tint, and his cheeks are sunken. After his aviator's jacket and black skull-pattern shirt are both torn to shreds, Nico begins wearing a tropical Puerto Rican shirt, decorated with parrots and palm trees, and with Isla del Encantorico written on it. His biceps are swollen and severely scarred from his fight with Lycaon, and after Reyna stitches them up for him, it gives Nico "a slightly creepy Frankenstein look," to the point that mortals on the street are scared off at the sight of him.
In The Hidden Oracle, Nico wears black jeans, a Ramones T-shirt, and a black leather bomber jacket, with his Stygian iron sword at his side.
In The Tower of Nero, he is wearing a black variant of the Camp Shirt with a skeletal Pegasus and the words CABIN 13, tattered jeans, and is barefoot. Apollo also notes that his hair has grown longer. Later on during the battle at the Tower, Apollo describes his clothes as being torn and battered from the fighting.
In The Sun and the Star: A Nico di Angelo Adventure, Nico wears a "black shirt with a white skull sitting beneath a red line and the letters AFI," and a leather bomber jacket. When he meets Amphithemis, Nico sustains slashes to the face from the mania that are likely going to scar. Although Chiron offers to help get rid of them, Nico decides to keep the scars.
==Personality==
In The Titan's Curse, Nico is ten years old. He enjoys playing with his Mythomagic cards that none of the others truly seem to understand. The Blood of Olympus reveals that he was obsessed with pirates even before that. He is clueless and very inquisitive. He likes Percy a lot as a big brother figure, but The House of Hades reveals that Nico had developed secret romantic feelings for him. Young Nico annoys Percy with his ceaseless questions, especially when he asks if Annabeth Chase was his girlfriend, which makes Percy consider "stuffing him in a meat-flavored sack and throwing him to the wolves." He is excited about finding out that he is a demigod (immediate response: "Cool!"), and starts to compare monsters to Mythomagic creatures. He feels abandoned when his sister Bianca, who practically acts as his parent, becomes a Hunter of Artemis. When she goes on a quest, Nico makes Percy promise to protect her. After her death, he develops a long-lasting grudge toward Percy for letting her die. Once he realizes that he is a son of Hades, he casts away his childhood interests and runs off on his own.
In The Battle of the Labyrinth, Nico becomes grim and solitary, and considerably more powerful. He says, "only the dead respect me... and only out of fear." His attitude may have changed both because of Bianca's death and Minos' manipulations. He believes that he will never be accepted by the living or Camp Half-Blood, much like how his father Hades feels out of place on Olympus. Nico is wanted revenge for Bianca's death, which he blamed Percy for. However, Nico forgives Percy after Bianca's ghost tells him that it wasn't his fault that she died. He also accepts the small figurine of Hades that Bianca wanted him to have.
He is so naive and gullible that he believes that Minos was actually helping him resurrect Bianca. Nico cares deeply about his sister, and his constant attempts to bring her back show that he would not give up without trying. Nico is very loyal to the Olympians, as he could have easily joined Kronos and the Titans, but chose to fight on the Olympians' side.
In The Last Olympian, Nico is quite sincere in wanting to help Percy with the prophecy and the war. However, he once tricked Percy into coming to the Underworld so he could gain answers about his mother, but he wasn't planning on Percy becoming imprisoned. By standing up to both Kronos and Hades, he reveals his bravery and boldness. In fact, the only time Nico is ever portrayed as terrified is in The House of Hades, when he was forced to face Cupid, implying that Nico's greatest fear is exposing his homosexuality. He prefers to be on his own, and does not want help from anyone. He keeps to himself, and his secretiveness causes plenty of problems throughout the series. Nico wants to help Percy and is very miserable at the thought that Percy did not trust him after his dad tricked him as well. By the end, they were back to a brotherly relationship.
Though he tries hard not to show it, Nico is plagued by incredible internal pain. For one: he is unable to come to terms with not "belonging" in the twenty-first century (due to the time he spent in the Lotus Hotel and Casino). For another: as a son of Hades, he is not accepted by other demigods. Worst of all, he fears being outed as gay and is desperate to keep that secret. After all, he grew up in 1940s Italy, when homosexuality was not accepted. 
Nico, apparently, also has tremendous, virtually indomitable willpower, since he was able to survive in Tartarus on his own while seeing the place in all of its ineffable horrors for the entire time that he spent there. Percy, who found even a few moments of seeing it maddening, marveled how Nico had managed to survive with his sanity. At some point during his horrifying journey through Tartarus, Nico encounters the goddess of misery Akhlys. She was impressed at how much sorrow and pain the son of Hades carried, claiming that there was little more that she could do to him. When Reyna shares her strength with Nico in The Blood of Olympus, she is horrified at how much pain and raw anguish she felt inside Nico. Even a portion of his pain is greater than the pain she had felt from her entire legion, when they fought against the giant Polybotes. When Reyna accidentally learns about Nico's homosexuality, she, much to Nico's surprise and relief, doesn't judge him. She still accepts him as a friend, just as he is, without hesitation. Reyna's acceptance likely gave Nico the courage to come out to a very surprised Percy and Annabeth. He admits to being past his strong crush on Percy and is now genuinely happy for Percy and Annabeth. Hence, Nico is finally willing to become more sociable and more open about himself and his feelings to others. He is no longer nearly so insecure about his homosexuality, and he is completely open about it six months later in The Hidden Oracle. 
In spite of Nico pretending not to know Percy in The Son of Neptune, he spoke very highly of him to Hazel, telling her that he is dangerous to his enemies and a valuable ally to his friends. Nico's relationship with Percy also shows how much he's grown and matured throughout the series. Nico is very caring to Hazel Levesque, his half-sister, and tries to help her as much as he can. His helping her sort of parallels with how Percy helped him in several cases. This shows that he loves his family, even his half-siblings. Unfortunately, after returning from Tartarus in The Mark of Athena, Nico is very different. He turns more inward and withdrawn, with his eyes becoming somewhat glassy like something in him broke permanently. Percy compares him to pictures of prisoners of war, which he notes Nico kind of was. Hazel states in The House of Hades that Nico has become more reclusive and morose, preferring to stay on top of the ship's mast, in solitude. Nico becomes much more easily angered, defensive, and takes to making creepy and humorless smiles. Nico, however, has happily smiled on two occasions: in The Last Olympian, right after he helps Hades defeat Kronos' army and gains his father's respect, and in The House of Hades after he and Frank defeat Gaea's monsters at the Necromanteion. In The Blood of Olympus, Nico notes that his facial muscles hurt when he smiles since he isn't used to making that expression often. Even though Nico seems to dislike being touched, he is shown to be very affectionate towards Hazel, having kissed her on the cheek several times. However, by the end of The Blood of Olympus, Nico begins to change and doesn't seem to mind when Jason and Reyna embrace him.
Nico's belief he will not be accepted by the living is complicated. After the war with Kronos is over, all the demigods of Camp Half-Blood welcome Nico cheerfully: as Percy puts it, "Hey, show up with an army of undead warriors to save the day, and suddenly you're everyone's best friend," meaning that when he saves them, the campers accept him. This helps lift Hades's curse from the Oracle. Sadly, however, Nico's popularity only lasted a few weeks, after which most campers did whatever they could to avoid the son of Hades and forgot he was at Camp, forging his feeling of not belonging. However, when Nico mentions his plans to leave for good, due to his lack of acceptance, Will Solace gets upset and tells him that there are actually many people at camp who are his friends or would like to be, but it is Nico who pushes himself away. Will also states that the camp did not reject him as he had thought. In spite of this, it is previously shown the dislike his presence receives. Albeit, this indicates that Nico may have misinterpreted the campers' reactions to him, or exaggerated it in his own mind, due to his fears of non-acceptance, although it isn't sure Will knows of all he went through before then. After Gaea is defeated, when Reyna tells the two camps about Nico's part in saving both of them and gives him a big hug, the crowd of demigods roared with approval, indicating that thanks to Reyna, both Camp Half-Blood and Camp Jupiter have finally come to truly accept the son of Hades once and for all. As a result, Nico decides to give Camp Half-Blood another try, seeing that he is finally accepted.
Nico can be extremely dangerous as he is a son of the Big Three. He is very unpredictable, and due to his sister's death can be somewhat mentally unstable as demonstrated in The Battle of the Labyrinth, and Octavian even claims to see a decent amount of ruthlessness in Nico. He has a short temper, just like Percy and Thalia. When Jason causes him to lose his temper in The House of Hades, Nico's fury was so intense, that it even scared Jason, who felt that a furious Nico was "more than he could handle." However, the greatest and most volcanic demonstration of Nico's fury happened in The Blood of Olympus, when he faced the psychopathic Bryce Lawrence. A furious Nico, in one horrible cry, unleashes a "flood of pain and anger" on Bryce, Reyna, and Coach Hedge, with the temperature around Nico dropping to freezing (turning the ground around him white with frost), Bryce's zombies instantly disintegrating, and a terrified Bryce himself turned into a mindless ghost.
This otherworldly demonstration of Nico's sheer rage when unleashed upon those cruel enough to invoke it was one of the most frightening events in the series. Suffice it to say that no one and nothing would be wise to provoke the son of Hades. 
By The Hidden Oracle, Nico is much happier and more involved in the camp. He spends most of his time with his boyfriend Will, and is no longer insecure about being gay (although he is still slightly uncomfortable with being called Will's "boyfriend" at first), and is considerably more relaxed around people, even roasting marshmallows on a campfire, joining in with the campers' sing-a-long, and helping Will tend to wounded demigods in the infirmary. Overall, Nico is very supportive of his boyfriend, even impressing Will's father Apollo. 
In The Sun and the Star: A Nico di Angelo Adventure, Nico is forced to confront his greatest demons with his return to Tartarus. As a result, Nico is finally able to mostly let go of them, and move towards true happiness, aided by Hades arranging a dream visit from Nico's mother and sister, to finally give him closure. As part of Nico's better outlook on life, he reaches out to Piper McLean and opens up to her about his grief over Jason's death, as well as strengthening their friendship, even offering Piper advice about being queer. Nico is also no longer embarrassed to openly show affection to his friends and boyfriend - kissing Will, and kissing Bob on the temple for support. Nico is, for once, left with optimism about the future and what it holds. Nico admits that even when he didn't want to let people believe that he was anything but a ball of darkness, he deep down wanted to have friends and be cared for, it's just that he had been unable to let go of all of the hurt and pain that he had been in.
===Fatal Flaw===
Nico di Angelo's fatal flaw is holding grudges, as Bianca's ghost tells him. In his case, it can lead to not wanting help or not asking to be saved in deadly situations because he simply doesn't like someone. For example, in The Battle of the Labyrinth, he did not want Percy to help him, even when Geryon was going to sell him to the Titans, and he did not want to go back in the Labyrinth with them. Bianca implies she also had the same fatal flaw in life, though it didn't lead to her death. In the fifth book, Nico tells his father, Hades, that he is holding a grudge that could end up killing the Olympians and the campers. Ever since The Last Olympian, Nico hasn't demonstrated this flaw in extreme degrees and tends to avoid holding grudges. He has learned from his previous experiences. 
His flaw resurfaces slightly in The House of Hades, when he still resents Annabeth for her freedom to love Percy openly and with reciprocation, despite his claims to Jason that he has "moved on." However, by the end of The Blood of Olympus, Nico is truly ready to move on. He tells Percy and Annabeth about his old crush, but admits that he has come to realize that Percy is not his type and that he is truly happy for Percy and Annabeth. Nico's crush and subsequent relationship with Will Solace signal the end of that internal conflict. In The Sun and the Star: A Nico di Angelo Adventure, a dream visit by his mother and his sister, arranged by Hades, helps Nico to get closure on their loss and any remaining anger and resentment that he might've felt.
===Fears===
As finally revealed in The House of Hades, Nico's greatest fear is of someone finding out that he is gay. Therefore, he never stayed at either camp for long and did not make connections of friendship with most people, so as to keep them from finding out, becoming more isolated than any other demigod. This fear about not being accepted due to his sexuality most likely originates from Nico's upbringing in the 1940s, when homosexuality was not accepted. On top of that, Nico was raised in a conservative catholic household, where homosexuality was likely not talked highly of. Hence, in The House of Hades, when Cupid forcibly makes Nico reveal his secret in front of Jason, the usually intrepid Nico is nearly reduced to tears. When Reyna accidentally learns about his secret in The Blood of Olympus, she, much to Nico's surprise and relief, doesn't judge him, and still accepts him as a friend just as he is (though she is still very surprised at this revelation), supporting him without hesitation. Reyna's unconditional acceptance and support was what most likely gave Nico the courage to finally come out to a very surprised Percy and Annabeth at the end of The Blood of Olympus, indicating that Nico has finally begun to overcome this immense fear and insecurity of his. And by The Hidden Oracle, it is indicated that Nico has finally fully overcome it at some point during the six months after Gaea's defeat, finally coming out and confessing his crush on Will Solace, with whom he begins an official romantic relationship. In The Sun and the Star: A Nico di Angelo Adventure, Nico is finally comfortable enough with himself to offer Piper McLean advice on being queer. While sharing stories with Gorgyra, Nico reveals that his fear comes from an incident when he was 8 in the 1940s, and he did experience homophobia. When Nico came out to the camp, it was after Juniper and the dryads misunderstood his request for help with a private picnic with Will, and instead threw Nico a huge coming out party. However, Nico still found the courage to come out to everyone, rather than denying being gay, and he publicly asked Will out. When none of Nico's worst-case scenario responses from the campers happened, it finally alleviated his fears and even inspired other closeted LGBT campers to follow his lead.
==Abilities and Tools==
===General Abilities===
To see this text, hit the "Expand" link to the right.
*ADHD: Like most demigods, Nico possesses inborn supernatural battle reflexes and senses.
*Dyslexia: Nico's brain is "hard-wired" for divine Ancient Greek instead of modern languages.
*Fighting skills: Initially, Nico shows more skill with his powers than his fighting skills. However, this might have been due to his majority lack of formal combat training at Camp, but he shows great skills. As revealed in a flashback in The Sun and the Star: A Nico di Angelo Adventure, Nico got overeager while first training with a sword, and scarred his own leg. In The Demigod Files, Nico showed decent combat skills when he was able to keep up with Percy and Thalia in a fight against a group of Keres. Not only did Nico emerge unscathed from the battle, but he easily defeated the Keres he fought, even quickly taking down the Keres who blitzed Percy. Later, Nico even fought the Titan Iapetus alongside Percy and Thalia (but he was quickly incapacitated). In The Last Olympian, Nico fights in the Battle of Manhattan, and emerges unscathed, implying excellent fighting skills, which impress even the Ares demigods. In The Son of Neptune, Hazel mentions being impressed the first time she saw him fight, suggesting that he honed his skills between the two series, possibly during his stays at either Camp Half-Blood or Camp Jupiter. Nico was even able to fight Gaea's army in Tartarus itself, though he was eventually overwhelmed by their sheer numbers. In The House of Hades, Nico fights the enormous monster army of Gaea, while holding the Scepter of Diocletian high, and emerges unscathed after the battle is won, implying excellent swordsmanship. During that battle, Nico single-handedly overwhelmed the entire group of mighty Earthborn, slashing them into mounds of wet clay with his sword. In The Blood of Olympus, though somewhat weakened from shadow-traveling, Nico is still able to single-handedly quickly overcome 6 Roman legionnaires (while protecting Will Solace), and it should also be noted that Nico was not even fighting to kill, only to knock them out. He later makes short work of Octavian's elite guard (6 huge dog-headed cynocephali). In the final battle with Gaea's troops at Camp Half-Blood, Nico fights at the front lines, managing to defeat numerous other monsters before being forced to leave in order to confront Octavian at one of the onagers.
*Superhuman Reflexes: Nico has shown great speed and reflexes, outpacing and taking down six trained Roman demigods in only ten seconds, while not aiming to kill and after being weakened from shadow travel. Nico also strikes first against Lycaon in The Blood of Olympus, while drained from summoning hundreds of bones, despite the Wolf King having caught an arrow in The Lost Hero, which Piper McLean couldn't see. In The Demigod Files, he quickly defeats a Keres who moved fast enough to strike Percy twice.
*Superhuman Strength: Despite his stature, Nico has shown to be unusually strong. In The House of Hades Jason notes that his arms are taught with muscles despite his eight days in the Twin Giants' jar. In The Blood of Olympus, when he fights the six Roman demigods, he kicks and strikes them with the pommel and flat of his blade with enough force to incapacitate them, despite their innate demigod durability and armor.
*Superhuman Durability: Nico has immense durability, able to take immense amounts of force and damage. In The House of Hades, when a boulder crashed into the foremast, Nico crashed to the deck under the spars and sails, but quickly shook it off. Later, when the Argo II is attacked by the Kerkopes and the ship lurches, he is launched out of his chair and slammed headfirst into the Celestial Bronze sideboard, causing a dozen plates and goblets to crash on him, only groaning from pain and later recovering. In The Tower of Nero, Nero, who has the fused power of Caligula and Commodus and later rivals Apollo in strength, backhands him twenty feet into a pillar, a strike he manages to go through despite being incapacitated. 
*Mythomagic: Nico's knowledge of the card game is superb, as he had the rare Africanus Extreme expansion deck, and remembers each figure, as well as the number of attack and defense moves of each. This lets him recognize figures of Greek mythology, as he was able to identify Dionysus, a Manticore, and even a Katobleps.
*Ancient Greek: In The Battle of the Labyrinth, Nico is able to summon the dead by chanting in Ancient Greek.
*Italian: In The House of Hades, Nico shows that he's fluent in Italian, being Italian-born. As shown in The Blood of Olympus, Nico's knowledge of Italian helps him understand some other Romance languages, such as Spanish and Portuguese. In The Sun and the Star: A Nico di Angelo Adventure it's revealed that Nico has memorized some passages of Dante's Divine Comedy in the original Italian.
*Willpower: Nico, apparently, has tremendous, seemingly indomitable willpower, since he was able to survive in Tartarus on his own, while seeing the place in all of its horror for the entire time he spent there alone. Percy, who found even moments of seeing it maddening, wondered how Nico had managed to stay sane.
*Pain Resilience: Nico was able to endure immense amounts of both physical and mental pain, notably scars inflicted by Lycaon which apparently "burned like acid", much to Reyna's amazement and respect as he carried through well in spite of it.
===Demigod Abilities===
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As a son of Hades, Nico is an immensely powerful demigod. He is considerably more trained in using his powers than most children of the Big Three, such as Thalia and Percy, due to his time spent in the Underworld and he states that he trains with the dead. In The Son of Neptune, Hazel stated Nico was one of the most powerful demigods she'd ever seen (to the point that she compared his power to that of a nuclear bomb). Hazel also states that Nico could rival Jason Grace, who also feared he couldn't beat him. However, meeting Percy left Hazel unsure which of the two might be stronger. In The Blood of Olympus, Reyna mentions that after being healed from his injuries by Hedge and resting for several days, Nico becomes significantly more powerful than ever before. Hazel once stated that she and Nico each control an aspect of Hades/Pluto's powers: death (for Nico) and riches (for Hazel), however, both, particularly Nico, have many other powers. 
*Geokinesis: Nico can control the earth, blackening into and controlling the black rock of the Underworld. Nico can open fissures in the earth that can swallow up creatures, rise flames, and trap them in the Underworld. He can cause earth tremors so powerful that they can shatter the pillars of a fortress and even vanish solid walls. He can also control the black walls of the Underworld, rising a jagged spire of rock the size of an eighteen-wheeler. His geokinetic abilities are only surpassed by his father, Hades, and rivaled by his half-sister Hazel Levesque.
*Necromancy: As a son of Hades, Nico has control over the dead, as well as many monsters of Hades, such as the Furies.
**Power Over the Undead: Nico can reanimate skeletons, summon Skeleton Warriors, put them to sleep, and destroy them. In The Battle of the Labyrinth, Nico was able to permanently banish Minos to the Underworld. In The Battle of the Labyrinth, he was able to summon over a dozen skeleton warriors all by himself. This is a powerful ability as it allows him to have an army anytime he wants. Summoning too many undead warriors at one time can cause fatigue, but by The House of Hades, he can summon a significant number without exhaustion. As shown in The Blood of Olympus, when he is angered enough, Nico can destroy even undead warriors that aren't under his control, which he does with Bryce Lawrence's zombie troops. Whenever he needs a personal chauffeur, Nico summons Jules-Albert, a loyal French zombie. In The Tower of Nero, Nico is able to control an undead Tauri Sylvestres. In The Sun and the Star: A Nico di Angelo Adventure, Nico is able to control the undead in Tartarus to help fight Nyx and her monster army.
***Telepathy with the Dead: In The House of Hades, Nico warns the Lemures of Venice (angry spirits) to stay away from him, Hazel and Frank by giving off a warning vibe.
**Sensitivity to Death: Nico can sense death as it happens or when it is coming; when a person close to him dies, it comes as a ringing in the ears. In addition to that, he has a deep knowledge of the Underworld and knows when a person's life is being judged in the Underworld. Nico can also sense when an immortal is fading, as in the case of Pan in The Battle of the Labyrinth. His powers are so great he could even sense that Percy and Annabeth were close to the Doors of Death within Tartarus. When Leo Valdez died, Nico sensed it, but he also sensed that something seemed different about his death, likely because of Leo's resurrection by Festus with the Physician's Cure.
***Life Aura: Nico can sense someone's life aura such as when he sensed when Rachel Elizabeth Dare's life aura flickered in The Last Olympian, and he told her "I could see you dying.", and when Apollo became mortal in The Hidden Oracle Nico sensed an aura of death around him — "a thick possibility of death."
**Seeing the Power of the Doors of Death: Nico, Jason, and Hazel can see and feel the power of the Doors of Death.
**Power Over Ghosts: As the Ghost King, Nico can physically manipulate ghosts, such as taking hold of them by hand or forcing them to be silent with a gesture.
***Summoning Deceased Souls: As shown in The Battle of the Labyrinth, Nico can summon the souls of the deceased by digging a pit, and filling it with food (though animal blood can also be used), and chanting in Ancient Greek.
***Releasing Souls: as shown in The Battle of the Labyrinth, Nico can release the souls of people that should have died but had somehow managed to cheat death, such as Daedalus.
***Ghost Transformation: As seen in The Blood of Olympus, Nico can kill mortals by turning them into ghosts, and forcing them into the Underworld for eternity. Nico has only ever done this to Bryce Lawrence. However, this takes away a lot of his strength and may cause him to fatigue as he did after he killed Bryce Lawrence.
***Skeleton Transformation: As seen in The Tower of Nero, Nico is able to kill others by transforming them into skeletons, similar to how he transformed Bryce Lawrence into a ghost. However, this takes a lot less power and effort with Nico causing a Germani to shrivel into a skeleton simply by touching his shoulder from behind. The skeleton was then under Nico's control until his distraction caused it to collapse into a pile of bones.
*Osteokinesis: As seen in The Blood of Olympus, Nico is able to summon and telekinetically control bones. Prior to his fight with Lycaon in Évora he could only summon a few bones and skulls, but during his encounter with the Wolf King, he was able to summon hundreds of bones, enough to temporarily trap Lycaon and his wolves. In The Sun and the Star: A Nico di Angelo Adventure, Nico transforms a finger bone into a literal skeleton key for Persephone's Garden. Later, Nico is able to create a half-pipe out of thousands of human, animal, giant and monster bones to break his and Will's fall into Tartarus, although Nico passes out from the effort afterwards.
*Death Trance: In The Mark of Athena, when he is sealed in the Bronze Jar, Nico shows that he can go into a hibernation called a Death Trance using the seeds of Persephone, which can only be eaten by a child of Hades. The Death Trance induces him to virtually die for a day, meaning he consumes significantly less oxygen and needs no other sustenance.
*Umbrakinesis: Nico has control over darkness and shadows.
**Shadow Travel: Nico can use shadows as a way of transportation; however, great distances tend to wear him out. The first time he shadow traveled, he passed out for a week. He has said that while learning to use it, he ran into walls and made accidental trips to China. He seems to have gotten better control over it because in The House of Hades, he implied he could use shadow travel to send the Argo II across a mountain range, but was too weak because of his time in Tartarus. When he recovers his strength by the end of The House of Hades, he decides to transport the Athena Parthenos across the ocean by shadow-traveling about three hundred miles at a time. However, as revealed in The Blood of Olympus, overexertion of shadow travel can cause the user's molecular structure to begin to fall apart, gradually turning them into shadows. Due to Nico pushing himself to bring the Athena Parthenos to Camp Half-Blood, he began to lose himself, even entering a "shadow coma," but after Gleeson Hedge heals him, he regains his strength.
**Shadow Absorption and Dissipation: As shown during his fight with Clytius in The House of Hades, Nico can also dissipate and absorb shadows using his sword, since he kept the Giant's dark aura from affecting his friends. 
*Thermokinesis: Nico has been shown to generate extreme temperatures to the point of combustion and freezing. However, he has yet to control the fire and ice he generates.
**Cryokinesis (limited): As seen in The Blood of Olympus, when Nico is infuriated, he generates an aura of intense cold, dropping the temperature to freezing, with the ground around him and the massive cairn turning white with frost.
**Pyrokinesis (limited): When Nico swallowed up the four skeleton warriors attacking him and Percy in The Titan's Curse, "flames erupted from the fissure." However, it is not known how powerful his control over fire actually is. 
*Hypnokinesis: As seen in The Blood of Olympus, Nico can navigate through "the dark dreamscape" of dreams better than most other demigods and is only somewhat surpassed by demigod children of Hypnos like Clovis, since he claims that dreams and death are "old friends of his." Hence, Nico has a higher degree of control over his dreams, the ability to astral project his consciousness, find and enter the dreams of other demigods. Reyna notes that Nico can have an extremely heavy sleep at times, to the point that he won't even budge if Coach Hedge does a goat-hoof tap dance around Nico's head. Later in the book, Nico puts several mortals to sleep by sending deep dreams their way. In The Sun and the Star: A Nico di Angelo Adventure, Nico was able to somewhat resist Epiales' nightmare, from inside the nightmare. 
*Phobikinesis: Nico radiates an intense aura of fear and death like his father, Hades, but to a much lesser degree. In The Last Olympian, this aura was so strong that Kronos' monsters initially backed away from him. In The House of Hades, he is shown to radiate death from nervousness, as when Cupid intimidates him, "the grass turned brown and wilted" at his feet, as if "poison were seeping from the soles of his shoes."
*River Styx Immunity (possibly): As seen in The Sun and the Star: A Nico di Angelo Adventure, Nico, as a son of Hades, can dip and swim in the River Styx without feeling burned. However, since this happened inside one of Epiales' nightmares, Nico might not actually have that ability.
===Magical Items===
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* Nico's Sword: A Stygian Iron sword. It is three feet long, and in The Last Olympian is described as being "black as a nightmare." It helps Nico to channel his power to control and summon the dead, and it can also drain souls to give the sword more power. Only Hades, his children, and Clytius can use Stygian Iron for their weapons. In The Sun and the Star: A Nico di Angelo Adventure, Nico and Will discover that Will can channel his photokinesis through the sword, increasing its power.
* He is seen wearing black armor in The Last Olympian with a skull-shaped visor.
* A skull ring shown in The Battle of the Labyrinth, The Last Olympian, and The Son of Neptune. Twisting it makes the nearest dead restless. He usually uses it to relieve tension. In The Sun and the Star: A Nico di Angelo Adventure, Nico has given it to Will Solace so that Will will always know how Nico feels about him with Will having given Nico a stylized coin that he had Jake Mason specially make for him.
* Mythomagic figurines and cards. He throws them into a fire in anger during The Battle of the Labyrinth.
* In The Battle of the Labyrinth, he had a pair of Daedalus' Wings, but after he used them, he threw them away in a trash can.
* Travel Rose: A red Travel Rose that he didn't use given to him by Persephone in The Sword of Hades.
* Pomegranate Seeds: Magical seeds from Persephone's Garden in the Underworld. If he places them on his tongue, he can go into a death-like trance that allows him to use less air and energy, in the event he is captured. This allows him to go into what is called a "Death Trance," which he uses to sustain himself during The Mark of Athena. As revealed in The Sun and the Star: A Nico di Angelo Adventure, they were given to Nico by Nemesis.
*Diocletian's Scepter: Nico obtained the scepter after he confessed his feelings for Percy, the scepter allows him to summon zombie legionnaires to his aid - he cannot control them, however, as he is neither a Roman demigod nor a Roman officer. He used the scepter to summon zombies at the Necromanteion and Pompeii to fend off Gaea's forces, after which it exploded.
*Pomegranates: In The Sun and the Star: A Nico di Angelo Adventure, Nico and Will steal three pomegranates from Persephone's Garden that they give to Menoetes.
*Gorgyra's Canoe: A magical canoe that is leant to Will and Nico by Gorgyra in The Sun and the Star: A Nico di Angelo Adventure for their journey through Tartarus. After Will, Nico, Bob and Small Bob's arrival at Camp Half-Blood, the canoe departs, presumably returning to its owner in the Underworld.
==Relationships==
===Love Interests===
====Percy Jackson====
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Nico and Percy met in The Titan's Curse after rescuing him from Westover Hall. Nico immediately asked if Annabeth was his girlfriend, why he and Thalia fought so much, and other questions, which made Percy want to feed him to the wolves and or strangle him. As Nico and Percy get to know each other, Percy feels bad for Nico after Bianca abandons him and joins the Hunters of Artemis. Percy reminded Nico of heroes from Mythomagic and pirates, and developed a crush on him. He thought he was a hero and could do no wrong. Before Percy left for the quest, Nico found him and asked if he was going on the quest with his sister Bianca and to protect her while on it. Percy promises that he will keep her safe. 
After Bianca dies, Percy felt very guilty for her death and immediately thought about who will tell Nico. It is Percy that decides to break the news to Nico. Nico takes it very hard and begins to hate Percy, blaming him for his sister's death before running away from camp, telling him he promised to protect her and that he wished he was dead. However, another reason Nico ran away was that he was afraid of his crush on Percy. After Nico ran away, Percy decided to keep his parentage a secret from Chiron and decided to be the hero in the Great Prophecy in order to make sure Nico wouldn't go through more pain. Percy searched for Nico all spring, to no avail. Nico was afraid of himself and afraid of his feelings for Percy, due to internalized homophobia, which persisted for years.
During The Battle of the Labyrinth, Percy has dreams about Nico and feels bad for him, but he became afraid that he would try to kill him as revenge to bring Bianca back. While searching for Daedalus in the Labyrinth, Percy runs into Nico at the Triple G Ranch. Nico becomes furious at Percy and orders him to go away, and thinks he will kill him. Percy calms down when he finds out that he wasn't planning to kill him, after Nico said Bianca's soul is worth more than his. He completes a job for Geryon to free Nico, even at the risk of Percy having to stay there himself if he fails. Even though Geryon double-crossed Percy, after his defeat, Percy asks Nico to stay on the ranch to keep him safe. In return, Percy helps Nico summon Bianca's ghost, who tells him to forgive Percy. The next day, Nico is jealous that Bianca appeared for Percy and not him, but he wasn’t as angry at Percy and needed time to think.
Nico rushed into the Labyrinth again after Minos told him Percy was in danger, showing that he indeed cared about Percy. However, when Percy found out Nico ran back into the maze, Percy wanted to return to the maze to find him. Percy and Nico were reunited at Daedalus' Workshop and Nico apologized to Percy, saying he was tricked by Minos and wanted to save him. Nico then saved Percy and the others by declaring himself the ghost king, finally becoming friends. During the quest, Nico saved Percy many times, especially when Kronos first rose from his sarcophagus in Luke's body; creating a large wall of black rock between them. He even aided Percy when the Titan Army began to attack Camp Half-Blood, but refused to stay. Also on the quest, Nico asked Percy if he really thought he would belong at Camp Half-Blood, Percy hesitated, thinking about how he had creeped him out when Nico declared himself the "Ghost King".
After the Battle of the Labyrinth, Percy ran into Nico in the woods and said that he could’ve sat with him at dinner, but Nico declined, saying he wasn't staying at Camp, and said he wasn't welcome at Camp. Nico wanted to discover his past that he knew nothing about. Percy wanted to argue, but he realized there was a reason why Pan didn't address him, and that he would have to find his own dark way. Percy then said he hoped he and Nico wouldn't be enemies, and Nico apologized for being a brat and said he should've listened to him about Bianca. The two parted ways when Percy gave Nico his figurine and they shook hands, and promised to keep in touch. Nico later appeared in Percy's apartment a few months later at his birthday party, and told him the fates of Minos and Daedalus. Nico wanted to tell him about how to bathe in the River Styx, but them asked if he had blue birthday cake. Percy realized he had never been invited to a birthday party before and invited him in, saying they had a lot to talk about.
In The Demigod Files, Percy and Nico meet again with Thalia Grace when the three of them are summoned and sent to the Underworld by Persephone. When he finds out about Hades' Sword being stolen, Percy doesn't want anything to do with Hades but Nico wanted to find the sword for his father and didn't want it to fall in Kronos' hands. Percy knew he wanted to impress his father and could see it in his face, so he decided to help him, not wanting him to go alone. Nico was amazed at Percy when he controlled the River Lethe and helped heal him after. Nico was also amazed when Percy defeated Iapetus. After the quest was over, Nico, Percy, and Thalia said their goodbyes on a balcony, and Nico decided to stay in the Underworld to help his dad. Percy and Nico shook hands and Percy had Nico promise to call him if he needed anything. 
In The Last Olympian, Percy and Nico were reunited, and Nico told Percy he did a good job scaring the satyrs. Percy asked if he was there to see Juniper and Nico blushed and said he just stumbled in on their conversation, most likely to hide his crush on Percy. Nico reassured Percy that Beckendorf's death wasn't his fault, and said he spoke to his ghost. Nico and Percy then talked about the plan for Percy to bathe in the Styx. Though Percy was unsure, he trusted Nico and went on with the plan. Percy and Nico met May Castellan and later Sally Jackson, where Nico pleaded with her to give Percy the blessing to bathe in the River. In order to gain information on his mother, Nico lead Percy to the Underworld to unknowingly speak to his father, Hades. Hades double-crossed Nico and put Percy in his dungeon, making Nico angry at him, since he wasn’t supposed to hurt Percy or arrest him, and he was only supposed to talk to him.
Nico later helped Percy escape and swore on the River Styx and said he didn't know what he was planning, but Percy was angry and wanted to strangle him, but knew there was no point in arguing. They escaped and Percy gave Nico ambrosia to heal from his fight, and caught him before he passed out again. After Nico and Percy met with Achilles, Nico had second thoughts on Percy bathing in the river, but Percy said it was his idea and to wait for him, and that if he died, he could be the hero of the prophecy. Nico was very scared when Percy woke up and asked if he was alright, and tried to protect him from his father and his soldiers. After it was done, Percy told Nico to stay in the underworld and help his father, since he owed him, which made Nico believe that he didn't trust him and apologized to him, which Percy didn’t accept. It is later revealed that Nico tried to make Percy fall in love with him by bathing in the Styx. 
Nico ended up doing what Percy said and convincing his father, showing up in the middle of the Battle of Manhattan to help Percy, and asked if it was too late to join the party. Nico encouraged Percy to go to Olympus, while he helped Sally and Paul, and said that he would handle the army. Percy later told the gods on Olympus that Nico proved to him that no one deserved to be left out, and that every god deserves a cabin at Camp. Nico also warned Percy and Annabeth that Rachel was going to Half-Blood Hill, and they went to find her. After the events of the book, one of the reasons why Nico left Camp again was his sadness of Percy and Annabeth getting together. In The Lost Hero, Annabeth mentions that he is looking for Percy.
In The Son of Neptune, Hazel introduces Percy, who lost his memory, to Nico. Nico was shocked when he saw him but regained his composure and shook his hand, shocked to see his crush. Percy and Nico studied each other warily, and Percy thought he knew him, and Nico responded, "do you?". Nico told Percy about the Second Titan War, but omitted details that Percy was involved in. Hazel later questioned Nico about this, and Nico told Hazel that he couldn't say much about Percy due to a promise he made with his father, but said he was one of the good guys and dangerous only to his enemies. Percy later questioned Frank Zhang about Nico, wanting to know more about him. At dinner, Percy questioned Nico, asking if they met before, but Nico lies and said he spent most of his time in the Underworld and unless he saw him there, they never met. Nico didn't want to talk to him much, and on the way to a senate meeting, Nico waved to Percy but went back to talking to Gwendolyn, indicating that he didn't want to talk to the son of Poseidon. However, Nico was proud of Hazel when she stood for Percy, letting him into the Fifth Cohort. He also explained to Percy how Thanatos and Pluto were different. After Percy got his memory back, Percy wanted to wring Nico's neck for keeping secrets from him, but he wanted to find him since he was Hazel’s brother.
In The Mark of Athena, Percy dreamed of Nico and found out he was imprisoned in a bronze jar. However, Percy had mixed feelings about Nico, and was still mad at him for tricking him to go to Hades palace. He was also mad at him for hiding his last from him and thought of scathing things to say to him. But he wanted to rescue him and couldn't stand seeing him in pain in a bronze jar, and didn't want him to suffocate him to death. He also wanted to find him because he knew where the Doors of Death were. In Rome, he helped rescue him with Jason and Piper, and was the most determined out of the three to rescue him. However, he was annoyed when he could barely crawl out of the jar, and wanted him to crawl more and groan less. When they went back on to the Argo II, Percy felt so sorry for him he couldn't muster much anger at him. Nico apologized to Percy for keeping his past from him and said he knew about both camps, but couldn't tell due to a promise to his father. Nico also told Percy the Doors of Death were in Tartarus. When Percy later fell into Tartarus, as Nico tried to save him, he had Nico promise to lead the Argo II crew to the other side. Back on the ship later, Nico was determined to rescue Percy and knew he would make it back from Tartarus. Nico said that Percy is the strongest demigod he knows, and that he and Annabeth would make it through Tartarus, but he was secretly unsure if he would live.
In The House of Hades, Percy realizes that Nico indirectly saved his and Annabeth's lives by reminding Iapetus also known as Bob that Percy is a friend even though Percy didn't visit him and Nico was the one who actually visited him in Hades palace. When Percy found out, he felt low and dishonorable, unworthy of having a friend. He realized that he wouldn’t of survived in Tartarus if not for Nico. Percy, when on the verge of death from Gorgon Blood, admits that Nico is another friend that he had not treated fairly. While on his journey in Tartarus, Percy realized Nico was stronger than he gave him credit for.
As for Nico, Nico missed him a lot and his voice broke when he mentioned him as being the sea expert. The crew offered Nico Percy's cabin but Nico refused. Nico's crewmates were confused why he would do anything for Percy if they hated him so much, and couldn't imagine him being kind to him. The Argo II thought that Nico hated Percy, but it is revealed in Croatia that he actually had a crush on him, to Jason, who kept the secret from the others. Nico said he was over his crush, but he wasn’t. Favonius also called Percy, though not by name, "The person Nico cared about most." When he rescued Percy and Annabeth from Tartarus, Nico accidentally held his hand for too long and let go. And Nico looked sad when he saw Percy and Annabeth holding hands. Percy was worried when Nico offered to transport the Athena Parthenos to Camp, but Nico angrily said that he’d changed since Tartarus. Later, Percy went to thank Nico for leading the crew to the House of Hades, and Nico said it was the least he could do after he saved him in Rome. Percy then told him about Tartarus and thanked him for helping Iapetus, and Nico said overlooking people can be dangerous. Percy then said he was trying to say thank you, and Nico told him to give him space, making Percy feel hurt. He was also confused as to who Nico was, as he wasn't a nerdy little kid or an angry loner anymore.
In The Blood of Olympus, Nico thought that Percy’s humor was juvenile, and thought he acted so much younger than him, even though he was three years older than him. However, Nico found it endearing, but also annoying. Nico resented Percy for his feelings but knew he would do anything for him. When Nico found out that one of the seven may die, Percy was his third priority after Hazel and Jason. Nico was grateful for Percy for saving him in Rome and letting him onto the ship, and the thought of him or any of the seven dying made him feel like he was back in the bronze jar. When Nico saw Hades in Portugal, Hades hinted that he knows about Nico's little crush on him. Nico was surprised when Reyna and Coach Hedge accepted his crush on Percy, which likely encouraged him to come out to him after. After he returned to Camp, he was genuinely happy for Percy going to college in New Rome, and Percy was happy for Nico staying at Camp. Nico then confessed that he had a crush on Percy, but not anymore, since he isn't his type, but still cute. He said that Percy was a great person and he was happy for him and Annabeth. Percy was too shocked to speak, oblivious to his feelings. 
In Camp Half-Blood Confidential, Percy and Nico are good friends. Percy, along with the rest of camp, supported Nico and knew about his relationship with Will Solace. At the campfire, Percy stared at Nico, stunned, when he sang and danced to a rendition of the hokey pokey. When Nico told the Camp about about the orientation video, Percy told him to look at what he started. Nico asked if he should stop them, and Percy smiled and said no and said to get popcorn ready. Percy and Nico later did the FAQ, where they both got annoyed at Annabeth when she yelled at them, yelling her name in unison. 
In The Sun and the Star: A Nico di Angelo Adventure, Nico is shown to still think very highly of Percy and to care about him, but he has truly moved past seeing Percy as anything other than a good friend.
====Will Solace====
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In The Blood of Olympus, it's hinted that Nico has developed an attraction to Will Solace, as they fought alongside each other. The two argue, but Will is shown to be able to withstand Nico's temper, and even order him around a bit. Nico develops an admiration for Will, who he hadn't thought greatly of before. At one point, Nico remembers his first arrival to camp in Apollo's sun chariot, and how Thalia had thought that Will's divine father was hot. While Nico didn't understand suddenly remembering this, it is most likely an indication of his budding feelings for Will, since Will is Apollo's son and shares physical traits with him. In the aftermath of the battle, Nico avoided Will, believing he was disgusted with him for allowing Octavian to kill himself, showing he cared very much about Will's opinion of him. To his surprise, Will is more upset that Nico didn't offer to help him, or more importantly, spend time with him after it was all over. Will ordered Nico to stay with him in infirmary for three days, and Nico "felt like a hundred skeletal butterflies were resurrecting in his stomach". Will also seems to reciprocate said feelings, or at the very least, is willing to be closer friends with the son of Hades.
In The Hidden Oracle it is revealed that shortly after Gaea's defeat, Nico finally comes out and confesses to Will Solace about having a strong crush on the latter, and the two begin dating, with Will at one point affectionately referring to Nico as his boyfriend. Will's father, the former god Apollo, is completely supportive of their relationship, due to him having had several mortal boyfriends himself. They continue their playful banter with each other, and are usually seen sitting close by, holding hands. In fact, Apollo claims that Nico and Will are so cute together as a couple, that it made him feel desolate, jogging his memories of the time he had spent with his mortal boyfriend Hyacinthus, one of Apollo's two all-time favorite lovers (the other being Daphne). Nico on his part, is always ready to help and support Will, such as when he tirelessly helped his boyfriend tend to wounded campers (notably Paolo Montes and Valentina Diaz). Nico also showed some jealousy when he caught Will staring at Paolo, but Will stated that it was nothing and that he was merely admiring how well his arms were functioning after surgery.
In The Tower of Nero, six months later, the two are still together. Throughout the book, both express concern toward the other during stressful situations. Will shows that he cares a lot for Nico, carrying a travel pillow for him to use while resting after shadow travel during their quest. During the Battle of Nero's Tower, when Nero slaps Nico aside, Will appears in the doorway and yells that no one is allowed to hit his boyfriend, and screams at the enemies to move out of his way so he can get Nico to safety and heal him. At the end of the book, Nico is comfortable enough to sit at the campfire with Will's arm around his shoulders. When Nico discusses potentially getting Rachel Elizabeth Dare from Paris if she needs help, Will comments that he hopes that Nico is planning a date night in Paris, but is aware that his boyfriend is actually trying to get some prophetic help. When Nico explains his desire to go to Tartarus to help a guy, Will questions if he should be jealous, but Nico explains that it's a Titan. Will makes it clear that he intends to support and join Nico on his dangerous journey to find out what happened to Iapetus and help him if need be. Rachel then gives them a prophecy, solidifying their inevitable quest together.
In The Sun and the Star: A Nico di Angelo Adventure, Nico and Will go on their quest together which tests their relationship as it brings up the various problems they have, particularly as they sail the River Acheron which brings their doubts to the surface. However, the experience brings them closer together and causes Nico and Will to confront and fix their problems. In the process, they discover that they can combine their powers, making them stronger together and admit their love for each other. With a new better outlook on life and the encouragement of his family to be happy, Nico is left with a sense of hope and an eagerness to build a future with Will.
===Friends===
====Jason Grace====
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Jason met Nico at Camp Jupiter at once point. Before rescuing him in The Mark of Athena, Jason voices his doubts on Nico's loyalties, infuriating Hazel, and wanted to leave him to die in Rome. Jason pointed out that it might be a trap and also found Nico's loyalties doubtful, because despite knowing about both the camps, Nico did not tell anyone. Jason had also learned from Percy about the incident in Hades' Palace (in The Last Olympian, not knowing what to think of him. Nevertheless, he still saved him, and Nico thanked him and the rest of the crew, saying he almost lost hope. Nico later told Jason about how they could save Percy by going through the House of Hades.
In The House of Hades, Jason is still creeped out by Nico, and doesn't want to go alone with him after hearing how he betrayed Percy in the past. Jason also thought that he had a tendency to hide in the shadows. He wished someone put a bell around his neck to be reminded that he was there, because he hid in the corner and blended into the shadows. He also thought he wasn't easy to figure out. He thought it was disturbing he spent more time with the dead then the living. He didn't get why Nico hated Percy so much but still took the Argo II to Epirus, didn't spend much time at either camp, and pushed people away. Nevertheless, Nico still trusted Jason and obeyed his command, and Jason tried to talk and bond with Nico, letting Nico share his news about meeting priests of Hecate to the crew, and told Leo to stop making jokes while he was talking. 
Jason was creeped out by the suggestion of going to go to find Diocletian's Scepter in Croatia with him. Jason was excited when Piper offered to go with him, but Nico rejected the notion of her going, and Nico had a look as if he was waiting for Jason to protest. Once they got to Salona flew Nico into the sky, which made Nico angry about being touched. He thought having Nico around was not reassuring when they went underground, especially with the glow of his Stygian Iron sword. Jason comforted him when Nico was nervous about confronting Cupid, even though he thought it's just a crush on Annabeth, and said it may be embarrassing, but it's just for the scepter. When the two arrive in Salona, Jason is grateful to have Nico there with him, and the two defended each other during Cupid's attacks, with Nico helping Jason up when he fell. Nico even let himself be bullied by Cupid so he could leave Jason alone. Jason was so shocked by what he saw from Nico's past that he was unable to move or speak. But Jason realized by Nico was so afraid, and realized he had a crush on Percy. Nico eventually was forced to confess that he had a crush on Percy, and Jason accepted him immediately, thinking about his perspective of being gay in the 1940s, and told Nico that he wouldn't tell anyone if he didn’t want to. Nico almost cried, and said he didn't like Percy anymore, saying he was young and impressionable. Jason said he had seen people do many brave things, but what he had done was the bravest. Nico brushed Jason off though.
After the events, Jason is a lot more concerned for Nico and even defends him when Leo calls him creepy, and never told anyone about Nico's secret. He was also surprised when Nico became buff. At Auster's palace, Nico lashed out and yelled at Jason for not being able to convince Auster to leave sooner, and that he had suffered too many embarrassments. Jason encourages Nico to take a risk be his friend and that everyone will accept him for being gay, and that's who he is. Jason also tells Nico to stop running away and stop hiding, which angers Nico, making Jason grab his sword believing a fight is about to start. Despite Nico's anger, Jason tells Nico that he is willing to be his friend.
At The House of Hades, Nico gives Jason the chalice first to drink and asks him if he trusts him, which he does without hesitation, signifying that he trusted Nico. At the battle, Nico and Jason stick by each other and Jason catches Nico and protects him from falling at one point. Jason and Piper stood at Nico's back and protected him while he was summoning ghosts with the scepter. Jason even promoted Frank to Praetor after Nico suggested he do so. The two also helped save Hazel and Leo. When Nico says he is going with Reyna to retrieve the Athena Parthenos, Jason said he didn't doubt his strength, but was still skeptical, but after Nico said he had changed since Tartarus, Jason trusts him and knows he will be okay. 
While Nico is gone, the two think about each other all the time. Jason is grateful for Nico and his actions at the House of Hades. Jason worries about him and is grateful that he went to bring the Athena Parthenos. Every time Jason sacrificed his food to Jupiter, Jason prayed that his father will help him. Nico, on the other hand, is still embarrassed about Salona and when Jason picked him up. Nevertheless, Nico's primary concern other than Hazel is for Jason. When Nico found out that anyone from the Seven may die, Nico felt he was back in the bronze jar. He was grateful for Jason and the Seven for saving him and Rome and welcoming him on the ship. Nico also thought of Jason's advice to come out of the shadows when Reyna was brooding in Buford, causing him to tell Reyna about Jules-Albert. 
At the battle to kill Gaea, Jason was happy to see Nico fighting with Camp Half-Blood, and the two talked and ran into battle together. Nico asked if everyone was okay, and Hoth worried about Leo, they charged into battle for him. Nico was also worried when Octavian wanted to fire an onager, and Nico said he shouldn't, because Jason or Piper would get hurt.
Two days after, Jason visited Nico at his cabin, and Nico was slightly disappointed when he showed up, and not Will Solace. Nico comforted Jason over Leo's death, and told him that there was nothing he could have done to stop him, and Leo knew what had to happen. When Jason asked if he may be still alive, Nico apologized, saying he wished he could say otherwise, but he felt him die. He felt guilty for squashing Jason's hopes, but he knew it wasn't fair to give him false They also talked about how maybe they don't need more prophecies for awhile, after they find out the Oracle was blocked. Jason tried to convince Nico to stay at Camp again, but when Jason finds out Nico is staying at Camp Half-Blood, Jason almost hugged him, but he realized he didn't like touching and apologized, but Nico said he was an exception. Jason then have him a bear hug so hard his ribs cracked. He talked about all the fun they will have, and said they can sit with each other, team up for sing along contests, and team up for Capture the Flag. Nico pretends to be annoyed, and asked if he was trying to scare him away, and Jason apologized, but said he was just glad. Nico believed that he's actually excited for him to stay. 
After Nico sensed Jason's death, he flew into rage and destroyed things around him, and began suffering from PTSD: seeing flashbacks, not eating or sleeping, and hearing voices from Tartarus. When Apollo confirmed his death to Nico in The Tower of Nero, Nico spoke Italian and ran out of the room, a thing he only does when upset. Jason was one of the first people Nico thought as a friend. Nico contemplated going to find Jason and bringing him back, but Nico realized that he sacrificed himself for a reason and it wouldn't be fair to him to bring him back. He didn't know where he was, maybe Elysium or Rebirth, but he knew he was okay and accepted his death.
In The Sun and the Star: A Nico di Angelo Adventure, Jason's death is one of the things that Nico's cacodemons torment him about. After returning from Tartarus, Nico contacts Piper and opens up to her about losing Jason and how hard it is for him.
====Annabeth Chase====
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Nico and Annabeth first meet in The Titan's Curse, when Annabeth helps save Nico from the Manticore, and ultimately ends up captured. Nico asked Percy if Annabeth was his girlfriend, frustrating him. When Annabeth came home, she kept the secret that Nico was the son of Hades from Chiron, and searched for him all spring, to no avail.
In The Battle of the Labyrinth, Annabeth was uneasy when she found out that Nico was communing with the dead, saying that spirits are untrustworthy advisors, and that they needed to go track down Nico in the Labyrinth. Annabeth became extremely worried when she thought Nico would come after Percy. When Annabeth and Percy found Nico at Geryon's ranch, it is revealed that Nico, to some extent, blamed Annabeth for Bianca dying and had informed Geryon about her. Nevertheless, after Percy saved them from Geryon, Annabeth told Nico that Bianca's death wasn’t Percy's fault and that Kronos would do anything to get Nico on his side, and that Bianca wouldn't want to be brought back to life by him. But this made Nico more upset, telling Annabeth that she didn't care about Bianca, and that if she did she would help him. But even after everything Nico said to her, Annabeth helped him summon Bianca's ghost and kept spirits away from him. She also told Nico that his sister was right when she told him that his anger will be his doom, and reminded him again that Kronos would do anything to get him on his side. The next morning, Annabeth tried to convince him to join the group, saying that Bianca just wanted him to be okay, and put her hand on his shoulder, but he brushed her off and walked away. After he left, Annabeth told Percy she was worried about him and scared he would talk to Minos again.
Two weeks after that, Annabeth got an iris message from Eurytion and learned he had left his ranch and went back into the maze, making her so worried about him she was queasy. She and Eurytion thought that he was talking to Minos again and knew he was in danger, afraid of what Minos wanted from him. However, Nico ended up choosing to side with Percy and try to save him, and Annabeth charged at Kelli, who had captured Nico in the first place, and Nico, in return, chose to save everyone, including Annabeth, when he declared himself the Ghost King, finally trusting Annabeth. After they escaped, Nico chose to accompany Annabeth a gift shop to buy a prism. When they went back into the Labyrinth, Annabeth and Rachel chose to guard Nico while Percy went to see Luke. Nico and the girls agreed that they needed to help Percy or else he'd mess things up, and they all saved him, and in return, Nico saved everyone again, including Annabeth, by making black Stone rise in front of Kronos’s fortress. When they all arrived back at Camp, Nico didn't want to stay, but when Annabeth put her hand on his shoulder and asked him to stay for her, Nico decided to stay, but only for her, possibly to mess with Percy. During the Battle of the Labyrinth, Annabeth, along with the others, helped Nico sit up as he healed.
In The Mark of Athena, it is revealed that Annabeth has always had mixed feelings about Nico di Angelo, and suspects that he had a crush on her ever since she rescued him from Westover Hall. However, Annabeth herself has no feelings for him beyond kinship, since he is too young, too moody, and has a certain darkness in him that makes Annabeth uneasy. Furthermore, she has always found it hard to "read" Nico and his actions. However, Annabeth still admits to feeling responsible for him, and can relate to feeling like Nico did after Bianca's death—a homeless orphan, drifting through the world alone. Annabeth was upset when she found out about Nico's imprisonment, and listened to the news sadly, shaking her head, but she wasn't surprised at all by the news, and figured out he would die on the Kalends of July. She also figured out rescuing him was a trap, but felt a responsibility to save him.
A few days later, when she was reunited with Nico in Arachne's lair, Annabeth wasn’t surprised that he was there, and felt it was only right for him to be there with him. Nico, in return, didn’t say much, but he told her the other side of the Doors of Death was Tartarus. Their reunion was cut short when Annabeth began falling into Tartarus, and Nico rushed to try to save her, using his strength to hobble in her direction. He even leaned over the chasm, reaching out to help her and Percy, to no avail. The last sounds Annabeth heard before falling was Nico and Hazel screaming for help. Later, when Nico arrived back on the ship, Nico reassured Leo that Percy Annabeth were not dead, and if they were he would feel it. He also said that Annabeth would make it through Tartarus, and that Percy would make it, especially with Annabeth on his side, showing he thought highly of the daughter of Athena. However, he was unsure if he could get her back safely. 
In The House of Hades, the Argo II thinks that Nico has a crush on Annabeth, including Jason, who learned from Piper. However when he and Nico went to Croatia, he thought his "crush" was bigger than he thought and was a deeper love. At first, Nico tried to lie to Jason, saying he left Camp half blood because he crushed on Annabeth, but then admitted that he wasn’t. Jason connected the dots and it is finally revealed that Nico was actually jealous of Annabeth, not in love with her, due to her relationship with Percy (his actual love interest), which is why Nico initially didn't want to be around her. Nevertheless, despite his jealousy, Nico led the demigods into the House of Hades to save Annabeth and Percy. After seeing Annabeth and Percy holding hands, Nico looks pained, showing that his secret crush on Percy is as strong as ever, although Hazel just thought it was because he went through Tartarus alone. As for Annabeth, in Tartarus, she was in disbelief when she found out Nico helped them, and said she had no idea what drove him, and couldn't figure him out. When he left with Reyna and Hedge, she wished I’m good luck, and he wished her good luck in return, without making eye contact.
In The Blood of Olympus, it is revealed that after her return from Tartarus, Annabeth approached Nico as he was tying up the Athena Parthenos. Nico was afraid she found out about his crush, but instead, she went out of her way to thank Nico for being nice to Iapetus (even before Percy did so), and telling the Titan that Percy is worth saving. While Nico is still very jealous of Annabeth, and wants to hate her, he cannot bring himself to, since Annabeth's gratitude was genuine and sincere, and she never overlooked or avoided Nico like most people. Hence, Nico admits to himself that it would have been far easier for him if she were a horrible person. Later in the book, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (even Annabeth) dying made him feel empty—like he was back in the dark Giants' Bronze Jar. By the end of the book, Nico finally finds the courage to tell Percy and Annabeth about his past crush on Percy, coming out for the first time. By that point, however, Nico has come to realize that Percy is not his type, and that he is genuinely happy for Percy and Annabeth. While Annabeth is certainly shocked at such an unexpected revelation from Nico, she smiles at the son of Hades and high-fives him. Nico is also happy when he finds out that Annabeth and Percy are going to college in New Rome the next year.
Nico and Annabeth are on good terms. In the Camp Half-Blood Confidential, Nico, Percy, and Annabeth help with the FAQ. Annabeth remarked that Percy and Nico were idiots and she would yell their names, and Percy and Nico would yell her name in unison and annoyance.
====Jem Asturias====
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In The Titan's Curse, Jem was a part of the rescue team called in by Grover, which also included Percy Jackson, Annabeth Chase, and Thalia Grace. As Nico and Jem get to know each other, Jem feels bad for Nico after Bianca abandons him and joins the Hunters of Artemis. Jem seems sad when Percy tells her at the end of The Titan's Curse that Nico has disappeared and notably tries to search for him the next few months.
During The Battle of the Labyrinth, Jem receives many dreams and Iris messages about what Nico is up to.
 
====Leo Valdez====
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In The Mark of Athena, Leo was suspicious of Nico's loyalties, due to knowing about both camps, and thought rescuing him was a trap. However, after Hazel fought with him and Jason, Leo decided to rescue him for Hazel's sake and apologized to her, even though he thought he was suspicious for a good reason, and knew he had to travel fast to rescue him before it was too late. Leo even helped pinpoint Nico’s location with Hazel and Frank, and rescued him, Percy, Jason, and Piper McLean On Nico's end, he was very grateful that Leo rescued him and thanked everyone, including Leo, for rescuing him. After Percy and Annabeth fell into Tartarus, Nico reassured him that they were alive and that if they were dead, he would feel it. However, Leo was creeped out by the son of Hades and did not like how he hesitated if Percy would survive.
In The House of Hades, Leo was very creeped out by Nico and said he gave him the freaky deakies, thinking his eyes were sad and empty as if he stared into Tartarus, which he did. Leo would often make jokes at Nico’s expense, which Jason would often chastise him for. Leo once commented to Jason and Piper that Clytius reminded him of Nico and wondered if they were related. Nico, on his end, was frequently annoyed by Leo's humor. While they were fighting the Ourae, Nico got annoyed when he said that masts didn't come from trees, and he frowned and said that they are from trees, and Leo retorted that it wasn't the point. And on the way to the House of Hades, when Leo kept joking, Nico told him he wouldn't keep his sense of humor for long. Nico also became more defensive around Leo after Croatia, due to being worried about what he would say while he was gone. However, Leo and Nico collaborated well on defeating the Ourae and both worried about Hazel while she was gone with Hecate. Later, when Nico fell a few days later, Leo hoped he was okay, and he wholeheartedly supported his plan to get Diocletian's Scepter, saying he wanted Pagan Zombies to fight with. After Leo came back from Ogygia, Nico was glad to see him and shook his hand.
In The Blood of Olympus, it is revealed that Nico greatly cared about Leo, since him and the rest of the Seven didn't overlook him like the others and welcomed him onto the ship, and learning that he (and any other of the Seven) may die made him feel like he was back in the glass jar again. Later, when he arrived at Camp Half-Blood, and the Argo II exploded, he was worried about Leo's fate and reassured Jason that he would be fine, but just in case, they charged into battle "for Leo". Nico eventually let the onager hit Festus and kill Leo, knowing that some deaths couldn’t be prevented, listening to his father, but almost lost his nerve knowing he let his friend be killed.
After his death, he honored Leo and the dead and oversaw the burial rites, and knew that Leo had made a real sacrifice. Nico thought that talking to the other demigods about Leo's death was the hardest part of him dying. Out of all the demigods, Nico the only one not mad at Hazel and Frank for what they did, because he knew what Leo did was a sneaky, twisted, ridiculously annoying and noble plan he would do. Nico knew better that Leo was dead, telling Jason so, and said that he felt his death. However, Nico was wracked with guilt of his death and replayed the scene of his death in his mind for two days after it happened, and wondered if what he did unnecessarily cost him his life. His death even led him to pray to his father for guidance for the first time. Even though Nico felt guilty himself of what happened, he reassured Jason and Hazel that it wasn't their fault. 
In The Hidden Oracle, it is revealed that in September, after the events of his death, he (and everyone else) received a parchment scroll from Leo saying what happened. Nico was very angry at Leo for not contacting camp after and would hold the scroll and watch it every time he wanted to be angry at him. In Camp Half-Blood Confidential, he was miffed at Leo she remarked that he was supposed to stay dead. Nico remarked to Apollo when they sat at dinner together that if he sees Leo again, he'll kill him. Nico hated being left in the dark. However, when Leo returned, Nico arranged a single file line at Camp to punch him and even made a ticket dispenser, taking numbers, leaving Leo to ask if that was really necessary, which the other Campers agreed. After the punching was done, Leo yelled for Nico and asked if he was done with the physical abuse, and Nico smiled, saying there are plenty of people on the West Coast who want to punch him.
====Frank Zhang====
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Frank and Nico met before the events of The Son of Neptune. Frank is not uneasy around Nico like the other kids at Camp Jupiter. Frank thinks that Nico is okay, though thinks he is mysterious and doesn't think he is as nice or as good looking as Hazel. Frank didn't know much about him though, or about his past. Frank even thought his father was cool, and knew it wasn't his fault that he ran the underworld. On Nico's end, Nico was amused by the son of Mars and smiled when he saw him, since he wasn't nervous around him like the others. Nico also explained to Frank that death was captured in the senate meeting. 
In The Mark of Athena, Frank wanted to save Nico from the bronze jar and was worried about how long he would survive in the jar. He was extremely angry at Jason and Leo for not wanting to, and lashed out at them. Frank, along with Leo and Hazel, helped track down Nico and was determined to save him. After he was rescued, Nico thanked everyone, including Frank, saying he had almost lost hope. Nico later reassured Frank that Percy and Annabeth falling into Tartarus wasn't his fault.
In The House of Hades, it is revealed that Frank is secretly scared of going to places alone with Nico, and thought he was quiet and ghostlike, and felt like he was from the past. Frank thought he seemed to dematerialize when he wasn't speaking, and didn't know what scared him more: Hordes of reckless ghosts, cow monsters, or being alone with Nico. Frank couldn't think of him being kind to anyone, other than Hazel, and wondered why he helped everyone if he hated Percy so much. He was even always scared of Nico. Frank was relived when Hazel went with them to Venice so he didn't have to be alone with Nico. But Frank still tried to be his friend and encouraged him to talk about his past and his childhood in Venice. Frank was angry at Nico and wanted to kill him after Hazel was poisoned, and wanted to strangle him. His anger subsided when it was revealed that he used to play Mythomagic too, however. And when he was turned into a plant by Triptolemus, he demanded that he be turned back, calling him "his friend", and slammed the minor god into a wall for not healing Hazel or Nico faster. Later, Nico called Frank brave for killing all of the Katobleps in Venice, but became shocked when he found out he actually killed all of them. 
Frank was worried about Nico after he became quieter after the incident, mentioning to Hazel that he doesn't think he plays well with others. Hazel thanked Frank for trying to be his friend, since he isn't easy to like, and Frank said he is used to people who aren't easy to like after being with his grandmother for years. Later, Frank trusted Nico to guide him into the house of hades. Nico and Frank fought off hordes of monsters together in the House of Hades, and it was because of Nico that Frank was promoted to Praetor, when Nico encouraged Jason to promote him. Nico even smiled and laughed when Frank commanded the ghosts and killed the ghosts, saying "That’s more like it! Let’s turn this tide!" The two collaborated well, with Nico summoning the ghosts and Frank commanding them. Nico later told Frank he had an arrow in his arm.
In The Blood of Olympus, Nico regarded Frank as one of his friends, not overlooking him like others, and when he found out he may die, he felt like he was back in the Bronze Jar again. Later, when he was back at Camp Half-Blood, Nico was the only person not angry at Frank for aiding Leo in his suicidal plan, since he knew that was exactly what Leo would've done. Frank visited Nico and Hazel in their cabin, and thanked Nico. Nico said Frank did great, and it was an honor to quest with him. He thought that it was a good sign he could talk openly about his lifeline. Nico told Frank that he wasn't close to death and he had many more adventures ahead of him. He told him to be good to Hazel, and that he was a good guy, though secretly jealous of his happy relationship. Frank asked Nico if he wanted to come to Camp Jupiter with them, and that he would always have a place in New Rome but Nico said he would stay at Camp, and that he would visit. Frank said he’d hope he'd see him again, and Nico promised to be flower boy at his wedding. Frank was flustered after he said that, and left. Hazel then chastised Nico for teasing him about that.
In The Hidden Oracle, Nico says that he doesn't see Frank often, since he's busy with the whole "Twelfth Legion Thing".
====Piper McLean====
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Piper first learns about Nico in The Mark of Athena, when she learns he is dying, but only thinks of him as Hazel's brother. However, even after Piper found out it was a track, she was still determined to save him, and reassured Hazel that she would. Piper also decoded what Nico was in the prophecy and how he must have found the Doors of Death. After Jason and Leo opposed rescuing him, Piper lectured them, saying that was cold and that Nico was dying, and went to comfort Hazel. While crossing the Atlantic, Piper was anxious to reach Rome to save him, and imagined what Nico was feeling- stuck in a jar with only two seeds left, no idea if he would be rescued. However, when Piper saw a horrifying vision in Katoptris that hinted at Piper, Percy, and Jason dying on the way to Nico and saw that saving him was too easy, Piper briefly hesitated saving him, but still wanted to save him and saw a vision of him lifeless, making Piper hope he was still alive. After Nico was let go, Piper shielded Nico from leopards attacking him and defended him. Piper then tried to pull Nico to safety, injuring herself in the process, signifying how Piper was willing to sacrifice herself for him. After Nico was rescued, he thanked everyone, including Piper, and said he had given up hope. Piper later asked Nico where in Greece the Doors of Death were. After Annabeth and Percy fell into Tartarus, Nico agreed with Piper that it wasn't Frank or Jason's fault that they fell into Tartarus.
In The House of Hades, Piper and Nico appear to be on good terms, with Piper trying her best to include him. However, Piper thought that he had a crush on Annabeth, and mentioned that to Jason. She offered to go to Dalmatia with Jason and Nico, but Nico objected to her going, saying that Diocletian may appear to Jason or him, but not to anyone else, because Piper might spook him. After Croatia, Piper noticed that Nico was acting nervous and cagey, like something major had happened there, and worried about him. Piper became concerned when he kissed Hazels cheek, since he hated physical contact, and thought he was almost saying goodbye. Piper also felt Nico’s defenses going up, afraid of what him or Leo would say about him when he was gone. However, Nico and Piper cooperated well going into the House of Hades and when Piper said the doors opened every fifteen minutes, Nico corrected her and said every twelve, and discussed a lot while walking. When they fought monsters, Piper stood at Nico’s back, and was concerned after he almost fell.
In The Blood of Olympus, Piper cared about Nico, and reassured Jason that he, Reyna, and Coach Hedge would be fine, and told Jason that after the war ended, everything would work out for Nico and that Jason had done what he could, being a friend to him. Piper could sense what was happening with Nico due to being a daughter of Aphrodite, sensing people's heartache, but never pressured Jason to talk to her about it. Later, when Piper met Zeus for the first time, she immediately asked him if Nico, Reyna, and Hedge were okay. Piper also believed Nico when he said that Leo indeed died. As for Nico, Nico greatly appreciated Piper for everything she had done for him, welcoming him on to the ship and saving him in Rome, and when he found out one of the Seven may die, including Piper, he felt empty, like he was back in the bronze jar. Nico was very worried about Piper when Octavian wanted to fire an onager, and warned him not to, because either Piper or Jason would get hurt.
In The Sun and the Star: A Nico di Angelo Adventure, Nico Iris Messages Piper after returning from Tartarus to talk about Jason's death and the impact that it's had on their lives. Nico offers Piper advice on being queer and the two promise to keep in closer touch, strengthening their friendship.
====Reyna Ramírez-Arellano====
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Nico and Reyna first met before the events of The Son of Neptune, where Nico brought Hazel Levesque to Camp Jupiter. Dakota mentions that Percy "should've seen Reyna's face" when Nico asked her to take Hazel in, hunting that it was not pretty. Reyna was suspicious of Nico, because children of Pluto were bad omens, and she thought he wasn't who he said he was. She thought of him as a traveling oddball, harmless as fauns, and a bad omen like the other Romans at Camp. She did reluctantly make him Ambassador of Pluto, though she didn’t know what to do whenever Nico came. Reyna was still suspicious of him after months, and didn’t believe him when he told him about the Gigantes being reborn. During a Senate meeting, Reyna thought it was suspicious how Nico knew so much about Alcyoneus, and said he sounded like he was "quite familiar" with him. However, Reyna would occasionally ask Nico questions, like when Gwendolyn came back to life, she asked Nico if it was a power of Pluto. In The House of Hades, Reyna was not against going with Nico to deliver the Athena Parthenos to Camp.
In The Blood of Olympus, the two eventually grow close over the course of their journey. Reyna lends Nico strength to Shadow Travel, and, as a result, she learns quite a bit about his past and the tremendous internal pain that he's been harboring. She is horrified at the amount of internal pain and raw anguish (even a portion of which is greater than what she had felt from even her entire legion during the battle against the Giant Polybotes. Reyna became very impressed with Nico after she found out how he kept the secret between both camps, survived Tartarus, leading the Argo II to Epirus, being imprisoned. When Nico learned that Reyna had seen his memories, Nico put his guard up. Reyna even began thinking of Nico as her younger brother in spite of herself, and wanted to give him her cloak as a blanket, but she stopped, telling herself that he was her comrade, not her brother. But by the time they made it to San Juan, Reyna had seen enough of Nico's pain that she tucked him in with her cloak anyway.
Nico, on his part, admits to "kind of" liking Reyna, even calling her his friend. When he learned more about Orion from Hades, he remembered that Reyna was being guarded by Coach Hedge and wanted to return to her immediately. Nico became a little upset when he had to shadow travel the Athena Parthenos across the Atlantic, because he was used to people asking him to do the impossible. However, he was surprised when Reyna asked him how she can help him, which was something no one really asked him. Nico told her to lend him her strength again. Reyna reassured Nico that he would make the jump.
When she was briefly taken away by the Hunters of Artemis, Nico is enraged, since he didn't want them stealing another important person from him, and ripped up the note Thalia gave him in rage. He is relieved to have finally found her again. Nico, however, is worried at how brooding Reyna had become after leaving Puerto Rico, and encourages her talk about what troubles her (much to his own surprise, since brooding was usually his own method of dealing with internal turmoil as well), reminding her of the numerous ghosts of Asphodel, who are unable to speak any longer, due to them never speaking out during their lifetimes, reminding Reyna that her voice is her identity, and that unless she uses it, she is "halfway to Asphodel already." Nico then tells Reyna about Jules-Albert, his French zombie chauffeur that Hades gave him that he never told anyone about. As a result, Reyna finally opens up to Nico and she tearfully describes how she killed her father in Puerto Rico, something she'd never ever told anyone up to that point, since patricide is an unforgivable crime by Roman law, because he knocked out Hylla. Nico is quick to comfort Reyna, insisting that it was a mania (with only her father's worst qualities) that she had killed, not her actual father. 
Reyna later witnesses him kill Bryce Lawrence after he cuts Reyna’s cheek and threatens to execute her for patricide (he found out she killed her father) and seems horrified at the ferocious display of Nico's infernal powers. At that moment, Nico accidentally generates a "flood of pain and anger" on everyone present, allowing Reyna to finally experience his hardships from his point of view and also see Nico's greatest fears and secrets (including his homosexuality and his crush on Percy). Reyna was shocked at the beginning and didn’t know how to process it at first, with him reminding her of her father, but then she realized how much she trusts him and how he removed some of her burden, and said that she trusted him, healing him for 3 days. When Nico woke up, he was worried of what Reyna would think of him, and apologized to her, worried that he poisoned another friendship. But to Nico's surprise and relief, she told him how much she trusts him and how everyone lets out the darkness once in awhile, and how they are friends. She did, however made him promise to not turn someone into a ghost again. Nico realised that Reyna wasn’t judging him, but that she cared even more now that she knew who he was. Reyna's unconditional acceptance and support was what most likely gave Nico the courage to finally come out to a very surprised Percy and Annabeth shortly thereafter.
In addition, Reyna appears to be in awe of Nico's powers, especially after learning that he also possesses hypnokinetic abilities. She also greatly admires Nico's immense tolerance to both physical and mental pain. Nico, in turn, respects Reyna quite a bit, and by the end of their journey to Camp Half-Blood, he even calls her the most courageous demigod he'd ever meet, and promises to not let her down. Reyna wants to hug Nico in return, but doesn't think the gesture would have been welcome, so she settles for a friendly handshake. When Reyna arrived at Camp with the Athena Parthenos, Nico yelled at the Camp about everything she had done for them, and that they should be grateful for her, something Nico barely did. 
After Gaea's defeat, Reyna tells the two camps about Nico's part in saving them, brings him out of the shadows, gives him a big hug, and Nico tearfully returns it, burying his face in Reyna's shoulder. The crowd of demigods roars with approval in response, indicating that thanks to Reyna, both Camp Half-Blood and Camp Jupiter have finally come to truly accept the son of Hades. Shortly before leaving Camp Half-Blood, Reyna promises Nico that he will always have a place in New Rome, and he promises to visit her, Hazel, and Frank often.
In The Hidden Oracle, Nico states that Reyna is busy with the whole "Twelfth Legion thing", hinting that they don’t see each other often.
====Dakota====
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Nico knows Dakota from Camp Jupiter and seem to be on good terms. Nico talks to the son of Bacchus in The Son of Neptune and Nico doesn't mind when Dakota says that Reyna has no idea what to do with him. Nico makes Dakota blush when he compliments him for standing up for Nico. The two later go to discuss war strategies with Vitellius and Don. 
In the The Blood of Olympus, Dakota and Leila are the second people to find out about Jules-Albert, his French zombie driver. They bond over their hatred for Octavian. Dakota and Nico seemed to trust each other, with Dakota listening to Nico's orders and Nico saying he counts on him. It is unknown how Nico reacted to his death.
====Rachel Elizabeth Dare====
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Nico and Rachel met in The Battle of the Labyrinth, where Nico saved everyone, including Rachel, by declaring himself as "The Ghost King". Nico later says that Rachel and Annabeth dragged him along with them, saying that saving Percy was the only thing they could agree on. In The Last Olympian, even though Nico didn't know her well, he was worried when she took Blackjack and went to Half-Blood Hill.
In The Tower of Nero, Nico and Rachel had become friends and quested together to stop Nero. Nico liked Rachel's paintings and called them amazing, while Rachel liked Nico’s "black and white aesthetic". Nico also trusted Rachel when they thought that the cows outside her house were dangerously The two later helped sabotage the vats with Will and the troglodytes to stop Nero from burning New York. Two weeks later, Rachel and Nico were at the campfire together with Apollo and Will, and Nico was very worried when Rachel got a prophecy, saying it wasn’t good, standing over her with a perturbed look.
====Gleeson Hedge====
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Coach Hedge is very protective of Nico and in return, Nico respects him. Nico, Reyna, and Hedge helped the Athena Parthenos to Camp Half-Blood. Nico also called the coach his friend, which was a huge step for him, considering he thought he never had any friends. When Nico displays his horrifying show of rage, Hedge does not judge him, but thinks his rage was dangerous and dark, but Nico was surprised he didn’t care that the thought that. Hedge didn't judge him when he found out he was gay either. Nico realizes that now that he knew who he was inside, he cared more about him, instead of wanting to push him away. Nico saved Hedge's life many times, like from Bryce Lawrence and Lycaon.
Hedge greatly cares about Nico's well being and asked him how he can help him, and also cared for Nico in a shadow coma for three days, using woodland magic, and didn't leave him behind because he was a part of the team. Later, when they returned to Camp Half-Blood, Hedge told Will about Nico overusing his powers, obviously concerned.
The two spent plenty of time together on the quest, including going shopping together at San Juan, buying matching shirts, and going to the Buford Zippy Mart. Nico is also very excited about his baby, and couldn't help but smile with happiness when Will, Lou, and Cecil mention the baby's birth.
===Family===
====Bianca di Angelo====
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Nico and Bianca shared a very close relationship. When they were younger they were inseparable, chasing each other in the front of a hotel as Hades and Maria talked. As their mother died when they were young, Bianca assumes an almost motherly role, bearing the responsibility that a parent would normally bear. Bianca was very overprotective and close with Nico, and Bianca had a tendency to argue with Nico a lot and get annoyed, like when they were arguing at the Westover Hall school dance, waving their hands. And when Nico said it was cool when he found out they were demigods, Bianca said it was not cool and that they weren’t demigods. Bianca also has a tendency to not believe Nico, like when he said when a bus driver had thorns. However, Bianca deeply loved Nico and said he was the only family she had left, feeling alone. Nico also loved Bianca, clinging to her and telling her that he was scared when the Manticore kept attacking them. Nico also stood up for Bianca when he called her an insufferable girl. It is mentioned that Bianca was strict at the movies she let him watch. The two did have happy memories together, like Nico and Bianca walking through the National mall in Washington D.C in the 1940s.
Because of Nico's dependency on Bianca, it led to her joining the Hunters of Artemis to be free of the responsibility of raising her brother, and was reassured that Camp Half-Blood would care for him. Bianca talked to Nico and told him that she was joining, and Nico became mad and grumpy at Bianca for leaving him. While on the bus back to Camp, Bianca whispered something in Nico's ear, but he scowled and looked away. However, Nico still had love for Bianca left, and he told Percy to join the quest to protect her, and made him promise to. On the quest, Bianca confided in Percy that she loved Nico but she wanted to know what It'd be like to not be a big sister 24/7. But Bianca proved that she still cared for Nico when she died trying to get a gift for Nico in Junkyard of the Gods, the only Mythomagic figurine he didn’t have. She then told Percy to give it to him and tell Nico she was sorry.
When Percy returned, Nico immediately asked him where Bianca was. When Nico found out she was dead, he threw her figurine on the ground and took all of his anger from Bianca on to Percy, and ran away from camp in tears. Nico mentioned that he also had nightmares of Bianca, and could feel her being judged in the Fields of Asphodel. 
While Nico was gone, he was approached by Minos, who offered to do a soul for a soul: Daedalus for Bianca. Nico wanted to do it and wanted his sister to be back. For months, Nico tried summoning Bianca’s ghost, but Bianca wouldn't answer. In desperation, Bianca sent an Iris Message to Percy showing Nico's state, badly wanting revenge against his sister's death and wanting revenge, and begged Minos on how to get Bianca back. He later summoned Theseus, and begged him on how to get his sister back, and how to do "a soul for a soul". Later, at the Triple G Ranch, Nico successfully summoned Bianca with the help of Percy and his friends. 
When Bianca appeared to Nico, Nico was excited to see her, and her face was sad, like she was dreading this for a long time, and told Nico that he had gotten tall. Nico questioned why she hadn’t answered him and she said he hoped he would give up, making Nico's heart break. Bianca told Nico not to try to save him and that Percy is right, putting her hand on his face. Bianca told Nico that he must forgive Percy, and that grudges are fatal flaws for children of Hades, and that he must promise her. She then told him to admit that he was mad at her, not Percy, and he was mad at her for abandoning him to join the Hunters, and she apologized for that. But she said he must overcome the anger. Nico was still in denial though, wanting his sister back. Bianca then started to tell him that if he loved him, to not bring her back, but then she said that Tartarus was stirring, and that she must leave. Nico didn't want her to leave, but Bianca said that she loved him, and to remember what she said. Nico cried that night about the exchange and was jealous of Percy that Bianca summoned him, but gave up on trying to get her back. After the Battle of the Labyrinth, Bianca said goodbye to Nico.
However, Nico saw Bianca another time after this, in The Last Olympian. She appeared to him when he was trying to summon Maria di Angelo, their mother, and Bianca warned him not to, saying she was the one ghost they were not allowed to summon, because the knowledge was too painful, and that holding grudges was dangerous for children of Hades. Nico said that he knew that, and told Bianca to stop trying to protect her, and that he wasn’t the same as he was before. Bianca told him he didn’t understand, but Nico brushed her off and put his hand through the mist, making her disappear. Nico also has a bit of self-hatred for not being Bianca, when Hades says she should of survived, not him. It was later mentions that he had seen her spirit a few times in the Underworld.
After the events of The Last Olympian, Thanatos was captured, and Nico used this as an opportunity to try to get Bianca back. However, he was saddened to discover that Bianca had chosen Rebirth. He soon rescued Hazel, and he became very protective over her, not wanting to lose another sister. Nico would sometimes accidentally call her Bianca, making Hazel have a taste of metal in her mouth, reminding Hazel that she wasn't Nico's "real" sister. In The Son of Neptune, when he told how she was dead to the others, Nico was still very saddened on it, and sad how he would never see her again. In The House of Hades, it was still hard for Nico to talk about his past and Bianca, because it saddened him. He eventually told Jason that Bianca was the only person who accepted him, and she died, not yet fully over her death. In The Blood of Olympus, he dreamt of Bianca.
In The Sun and the Star: A Nico di Angelo Adventure, Hades arranges for Bianca and Maria to visit Nico in a dream, giving Nico closure over their deaths. Nico's family express their pride in him and tell Nico to go and be happy with Will for himself. Before Bianca and Maria disappear, Nico notes that they seem to be completely at peace.
====Maria di Angelo====
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Nico and Maria were very close when they were little, and they visited Dalmatia once in 1938. One of Nico's prized memories of her is him and her walking hand in hand in the Venetian canal. Maria was a great mother who cared for her children, and was determined to live with them and protect them. It is mentioned that Maria raised Nico and Bianca in a conservative Catholic family. When Nico was an adolescent, Maria fled Italy to escape Mussolini in WWII, to protect her children. 
When Nico was ten and Bianca was twelve, they ran around on the porch as Maria and Hades discuss how Hades can bring her to safety to protect them from Zeus, though his offer of building her a palace is declined. Hades wanted to send them to the Lotus Hotel to protect them, but Maria declined, saying the children needed their mother. Zeus destroys the hotel they were staying in in an attempt to kill him and Bianca. Nico and Bianca then witnessed Maria's death, and stared at her uncomprehendingly, not understanding what happened to her. Nico and Bianca's memories of her were then wiped by the River Lethe.
In The Battle of the Labyrinth, Nico was very umpatient to learn about his mother, due to having no memories of her. By The Demigod Files, Nico's memories were back enough to recognize his mother, and when summoned by Melinoe, Nico was sad to see her and said "mama"? In The Last Olympian, Nico summoned his mother to see what happened to her, and Bianca tried to stop him, but he did anyway. He expected to see her, but instead saw her death. Nico was shocked when the ordeal was over.
By The House of Hades, Nico couldn't remember much about Italy and his mother, but had some memories of her back.
In The Sun and the Star: A Nico di Angelo Adventure, Hades arranges for Bianca and Maria to visit Nico in a dream, giving Nico closure over their deaths. Nico's family express their pride in him and tell Nico to go and be happy with Will for himself. Before Bianca and Maria disappear, Nico notes that they seem to be completely at peace.
====Hades====
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Nico and his father share a complicated relationship. They are both extremely similar, especially in their ability to hold grudges. Both of them are also somewhat cynical. However, Nico seems to have a stronger tie to his friends, while Hades seems to have a much darker view of his siblings. Nico is also a more genuine person than his father- Hades can be crafty, as seen from how he used Nico to attempt to trap Percy.
Hades occasionally remarks that it would've been better if Bianca survived, much to Nico's dismay, though deep down, he cares a great deal for his son, as his gaze softened "from steel to stone" when he saw him. He also wants to redeem himself in the Olympians' eyes through Nico, believing his son to be the demigod of the First Great Prophecy. Nico also appears to want to please his father, and beams with happiness when he gains Hades' respect after Kronos' defeat. At the same time, Nico is unafraid to challenge his father in order to do what Nico believes is right. 
After the Battle of Manhattan, Hades begins trusting Nico with much more information, and even tells him about Camp Jupiter and the Roman demigods, trusting Nico not to share this knowledge with anybody else until the time is right. Hades might have foreseen that Nico was destined to find the Doors of Death and lead the Seven Heroes of Olympus there. 
In The Blood of Olympus, Hades and Nico speak in Évora. Hades tells Nico that "some deaths cannot be prevented" which alluded to Octavian's death. Hades also praises Nico for his past accomplishments, letting him know that he is proud of his son, and that he wants Nico to be happy. Their relationship seems to have improved, since Hades' tone is described as "almost gentle" while he is taking to his son, while Nico (who usually dislikes being touched), feels reassured when his father briefly touches his shoulders. It is later revealed that Hades gave Nico a zombie chauffeur as a birthday present once, since he was trying to be more like normal mortal parents, who normally drive their children to places. 
In The Sun and the Star: A Nico di Angelo Adventure, Hades is revealed to be the one who sent Nico on the quest to rescue Bob. Afterwards, Hades arranges for Bianca and Maria to visit Nico in a dream, giving Nico closure over their deaths. Nico's family express their pride in him and tell Nico to go and be happy with Will for himself. Before Bianca and Maria disappear, Nico notes that they seem to be completely at peace. Hades himself reveals that he has a great deal of pride in his son and only wants him to be happy and is now willing to break the rules for Nico, having rethought his behavior due to the changes that Percy Jackson caused in the gods.
====Persephone====
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Nico and his stepmother Persephone mutually dislike each other, as he is a reminder of Hades' affair with Maria di Angelo, who Persephone is jealous of. This same dislike appears between Percy and Amphitrite, as well as Thalia and Hera. Persephone appears to take it to another level through turning Nico into a dandelion as stated by him in The Demigod Files when Percy, Thalia, and he ended up in the Underworld together.
In The Mark of Athena, it is revealed that Nico carries around some pomegranate seeds from Persephone's garden in case of an emergency, and so uses them when he is trapped by the twin giants. It is unknown how Persephone feels about Nico using an item from her personal garden, or if she is aware at all.
====Hazel Levesque====
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Hazel and Nico first met a month after the events of The Last Olympian, when Nico went into the Underworld after Thanatos was captured to bring Bianca back from the dead. However, she chose Rebirth, and instead, Nico found Hazel in the Fields of Asphodel. Nico could immediately sense that she was a daughter of Pluto and that she remembered her past. Nico told her that he came to being his sister, Bianca, back, but he failed, but he told Hazel that she needed another chance and come with him. While on their journey to the world, Nico brought Hazel to Persephone's Garden and told her about the pomegranate seeds: a last resort food only children of Hades/Pluto can eat. Nico brought Hazel to Camp Jupiter to meet Reyna and Jason, and Nico told them that he found her in New Orleans. Hazel first thought that Nico was a scrawny white boy that couldn't fight and laughed when he first called his sword "Stygian Iron". However, Hazel soon realized that Nico was the most dangerous demigod, even more so than Reyna, Jason, or Octavian. 
In The Son of Neptune, Hazel and Nico are on good terms, with Hazel greatly caring about Nico as the only family she has left. Nico and Hazel discussed a lot about current events going on, and both figured out that Thanatos was captured, and knew a lot about the Gigantes, especially Alcyoneus. Nico also helped Hazel with her blackouts and helped her control them, and was the only one who knew about Hazel's past. Nico liked to remind her that she could make things right and that she belonged at Camp Jupiter. However, Hazel sometimes gets very frustrated with Nico, especially when he keeps secrets from her, like refusing to tell her where Percy came from, and sometimes can't trust him. Nico would sometimes accidentally call Hazel Bianca, making Hazel jealous and her mouth taste like metal, reminding her of his "real" sister. Hazel also sometimes dreaded when Nico came to camp, because all of the Romans (except for Frank and Dakota) saw it as a bad omen. However, Nico tried to protect her whenever he could: healing her cuts when she ran to the Mess Hall and yelling her not to apologize for her blackouts. Nico also had a tendency to call Hazel his sister, and "sis" when he was especially proud. Nico was very proud of Hazel when she stood for Percy. The two also discussed Alcyoneus at the next senate meeting.
Later, when Hazel left for Alaska with Frank and Percy, Nico pulped Hazel aside to wish her luck and say goodbye. She hoped he would stay at Camp to defend it, but Nico said he was going to the Underworld to help his father and try to find the Doors of Death. Hazel told Nico to be careful and was worried she would never see him again. Nico told Hazel to take care of herself and took her hand, saying he wanted to give her a chance at Elysium and didn't want to lose her again. Hazel knew he was thinking of Bianca, but for once, she wasn't jealous of her, and just wanted to spend more time with her brother. Later, Hazel got a vision from Gaea who told her that Nico was manipulating her and using her, which she didn't believe, and then told her that she captured him and he would die soon, making her cry and panic. She didn't want to believe that he was captured, but she had a feeling that she was right, and worried about losing the only family she had left.
In The Mark of Athena, Hazel was terribly worried about Nico. She found out from Nemesis that he only had six days to live and was determined to help him. After Hazel found out that Nico was in the bronze jar, Hazel burst out sobbing and was even more determined to rescue him. Hazel became furious at Leo and Jason for suggesting that they should leave him in Rome to die, storming out of the room. However, she forgave them when they apologized. Hazel later went to track down Nico's location with Frank and Leo. After she rescued Nico, Hazel sat with Nico and gave him Ambrosia as they spoke. Nico told Hazel about Tartarus and how he found the Doors and arrived in Rome. Hazel later helped Nico to his feet to speak to the group, and held his shoulders as he coughed until he could stand again. After Percy and Annabeth fell into Tartarus, Hazel agreed with Nico that they were alive.
In The House of Hades, Hazel and Nico were very close, with Nico mostly spending time with her. They both cooperated well with the Ourae and they both went to Venice with Frank to get barley cakes from Triptolemus. Hazel and Nico both knew secrets about the House of Hades that they refused to tell the others, showing how they trusted each other. Hazel felt that Nico radiated old energy and felt that he didn’t belong in the modern world. Hazel and Nico understood and shared each other’s sadness, knowing children of Hades rarely had happy lives. Nico and Hazel often worried about each other's well being. Nico worried about Hazel when she went to see Hecate and blamed himself when she was poisoned by Triptolemus, even threatening the god to heal her. As for Hazel, when Nico fell against the ship walls and goblets fell on him, Hazel stayed to take care of him. And after Venice, Hazel often worried about Nico, who became even more reclusive and morose, and from everything he had gone through. However, Nico began to show Hazel affection, getting closer, giving her a kiss on the cheek when she was seasick.
After they went through the House of Hades, Hazel called Nico to her. Nico kissed Hazel on the forehead and told her that the ghosts were right, only one of them would make it to the Doors, and they were right. Nico then said that she made her father proud. Hazel then cupped her hand on his face, saying that she wouldn't of defeated Clytius without him. Hazel noticed that Nico had been crying. Hazel wanted to know so sadly what was going on with him over the past few weeks, but was so glad to have her brother there with her. Hazel and Nico then helped the group Shadow Travel back to the ship, combining their strength, holding hands. Hazel glanced at Nico soon after and saw pain in his eyes, looking at Percy and Annabeth hold hands, but she thought it was because he went through Tartarus alone while they had each other.
In The Blood of Olympus, Nico and Hazel were very worried about each other. Hazel asked Artemis if Nico was okay when she went to Delos. Nico, meanwhile, missed Hazel very much and his primary concern was for Hazel out of the Seven. When he found out that one of the seven, including Hazel, may die, he felt empty again, like he was back in the bronze jar. He was very grateful to Hazel and the others for rescuing him in Rome and welcoming him on to the ship.
When Nico reunited with Hazel, Nico was the only demigod not angry at Hazel (besides Frank) for Leo's death, because he knew that’s what Leo would’ve done. Nico and Hazel also knew that Leo was dead for good. Nico and Hazel shared Hades' Cabin together, with Nico grateful to be with his sister. Hazel and Frank offered for Nico to come live at Camp Jupiter with them, but Nico declined, opting to stay at Camp. Nico then told Frank to be good to Hazel and that he would be flower boy at his wedding, embarrassing Hazel. After Frank left, Hazel chastised Nico for this. They both agreed that they would miss each other and Hazel made Nico promise that he would visit. Nico congratulated Hazel on becoming Centurion and asked if there were rules against Centurions dating praetors, which Hazel said was the least of her problems. Nico also told Hazel that she wasn't the same girl he brought to Camp Jupiter and that she was confident now, and Hazel thanked him for it, but Nico said it was because of Hazel she was. Hazel and Nico then discussed Leo's death and he reassured her that it wasn't her fault. Hazel expressed guilt over him dying alone and Nico hugged her and tucked her in as she cried herself to sleep. The next morning, he made sure he and Jason didn't wake Hazel, as she was still asleep.
In The Hidden Oracle, Nico said that Hazel was busy with "The Twelfth Legion thing" implying that they didn't see each other much. In The Tyrant's Tomb, Hazel mentions that Nico could help cure Apollo's scratch.
===Gods and Titans===
====Apollo====
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Apollo and Nico first meet in The Titan's Curse. Nico is excited and giddy around Apollo and asks him a lot of questions, while Apollo answers them and gets along with him fine. At the time, he sees Nico as a little kid.
Nico and Apollo seem to be on good terms, since he is the father of Will Solace, Nico's boyfriend. The two interact in The Hidden Oracle and Nico tells him of the whereabouts of the seven. Apollo sees the son of Hades as a capable fighter, and Apollo is supportive of his relationship with Will, even if he doesn't know why he would be attracted to a son of Hades. He thought that him and Will reminded him of him and Hyacinthus, making his heart hurt. He also liked his Ramones shirt, thinking he had good music taste. Later, Apollo helps Will and Nico heal Paolo Montes after he loses a leg. Nico also comes to Apollo and Meg McCaffrey's going away party. Nico later helps heal Apollo with Will, saying that he and Will were both worried about him. Nico helps Apollo defeat Nero and the Colossus Neronis. 
In The Tyrant's Tomb, Apollo almost wishes that Nico and Will were there after he gets poisoned with a zombie infection. However, Apollo recognizes that the wound is likely even beyond his son's ability to heal and that it is better for Nico and Will to be as far away from the danger as possible.
In The Tower of Nero, it is revealed that Apollo thinks very highly of Nico, thinking that he is someone you’d want on your side and never as an enemy. He thought he was brave for all that he had been through, having more resilience than Stygian Iron, from Tartarus to accepting his identity as a gay man. He wanted his help for the quest to Nero's Tower, and he accepted it. Apollo was later skeptical when Nico told him about the troglodytes, but he later believed him, showing his trust in the son of Hades. Nico collaborated with Apollo also, shadow traveling with him, and Apollo trusting him to be able to Sabotage the vats. Later, when Apollo went through Nero's tower, Nico helped him kill Gauls in the hallways and kill Nero. After the battle, Nico and Will help Apollo prepare for his final confrontation with Python.
Two weeks after the defeat, Apollo visited Nico and Will at Camp Half-Blood, since Apollo was worried about the fate of his friends. Apollo was worried about Nico hearing Jason's voice, but Nico reassured him that it wasn't, and that he knew he was in a better place. Apollo was shocked when Nico and Will wanted to journey into Tartarus to save Bob, but he didn’t want to tell demigods what to do anymore.
====Dionysus====
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Nico met Mr. D in The Titan's Curse, being very excited and giddy to see him, knowing him from Mythomagic. He called him "The Wine dude" and talked to him about all the defense points gods had in the game. Dionysus, on his end, was very annoyed by Nico and gave him a look of loathing when he called him "the wine dude."
In The Tower of Nero, it is revealed that Nico and Dionysus had grown very close, with Dionysus thinking he had been through too much. After Jason died, Nico and Dionysus began eating most meals together, with Dionysus even letting him sit at his table, something he never did. Dionysus helped Nico make sense of the dreams he was having, figuring out what was real and what wasn't. Dionysus didn't want Nico going on the quest with Apollo and talking to troglodytes, saying it was bad for his mental health, but Nico insisted on going, and an annoyed Dionysus let him.
In The Sun and the Star: A Nico di Angelo Adventure, following Nico's return from Tartarus, Dionysus greets him with a hug, showing his care and concern for Nico despite his usual gruff demeanor.
====Cupid====
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Cupid is the only god the son of Hades truly fears, having grown up in a time where being romantically involved with anyone other then someone of the opposite gender was unthinkable and persecuted against. Upon learning who they had to meet to get Diocletian's Scepter, Nico panicked. The longer Nico was in his presence, the more the god of love pressured Nico into revealing that he had a romantic attraction to a male friend. 
After the son of Hades was forced to admit his crush on Percy, Cupid became visible and apologized for forcing the information out of him before leaving and granting them the scepter, showing that the god had some sympathy for Nico.
====Iapetus/Bob====
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After Iapetus lost his memory, Nico would visit him at his father's palace from time to time. The son of Hades managed to convince Bob (Iapetus) that Percy Jackson was a good person, which would eventually lead to the Titan helping Percy and Annabeth Chase reach the Doors of Death from inside Tartarus.
In The Tower of Nero, Nico reveals that he feels guilty for Bob getting left behind in Tartarus and possibly being destroyed. Nico's description of Bob, before Nico explains that he's a Titan, causes Nico's boyfriend Will Solace to wonder if he should be jealous. Nico reveals that he thinks that a voice that he's been hearing calling to him from Tartarus might be Bob, suggesting that his friend survived. Nico intends to travel to Tartarus to try to find out what happened to Bob and help him if he can.
In The Sun and the Star: A Nico di Angelo Adventure, Nico and Will successfully rescue both Bob and Small Bob from Nyx and bring them back to the mortal world.
====Nyx====
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Initially, the son of Hades feared Nyx. During their first encounter, she cornered Nico in her realm and severed him the mental toll he was taking, sadistically cooing him as he sobbed. After learning Nico had adopted a more positive outlook, Nyx started tormenting his dreams. She would show the son of Hades his worst memories and fears to punish him, stoking his fears. Nico was so traumatized by this encounter that he suppressed some memories of it, and started fearing Nyx more than Gaea.
After they meet a second time, Nico demanded Nyx release Bob. The goddess refuses, and attacks him and his friends. After Nyx introduces him to his cacodemons, Nico is overcome with negative emotions, much to her delight. However, he eventually accepts the demons as a part of him, and frees them, much to the goddess’s anger. After the son of Hades and his companions escape, they watch as Nyx is unable to cross the River Acheron, and listen as her curses of vengeance grow quiet as they sail away.
===Others===
====King Minos====
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Shortly after Nico initially ran away from Camp Half-Blood, he was found in the Labyrinth by the ghost of King Minos, who intended to manipulate the son of Hades into killing Daedalus in revenge for his unjust, however much deserved, death. Supposedly, Minos' goal was to help Nico trade Daedalus' soul for Bianca's resurrection, but along with revenge, Minos wanted to use Daedalus' soul to gain his own resurrection instead. In order to gain Nico's trust, Minos leads him through the maze of the Labyrinth, saved him multiple times, and taught him how to utilize the infernal demigod powers he got from his father. It is most likely that Minos was also the one to teach Nico to shadow travel. 
In the end, however, Nico realized Minos' malevolent goals, and banished him back to the Underworld, stripping him of his Ghost King title, and taking it for himself.
Years later, in The Blood of Olympus, the son of Hades has several flashbacks of Minos in his dreams. It is also revealed that Nico's experience with Minos made him realize that most specters held only as much power as one allows them to. Hence, the son of Hades has learned to shield himself from specters' influence, and can even turn the tables now, bending them to his will.
====Octavian====
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As seen in The Son of Neptune, Octavian, much like most others at Camp Jupiter, thinks of Nico as just a somewhat creepy traveling outcast, considering the Ambassador of Pluto to be as harmless as a Faun. However, Octavian does grow suspicious when Nico seems to know about Alcyoneus in the meeting.
By The Blood of Olympus, Nico comes to absolutely despise the self-proclaimed Pontifex Maximus (to the point that his throat "constricted with hate" while just thinking about Octavian), and even considers personally assassinating Octavian without any qualms. Nico notes how different Octavian is from his love interest Will Solace, and describes the former as looking like a watered-down, unhealthy version of Will, without anything in him that makes a child of Apollo special. Octavian, on the other hand, seems to have finally come to appreciate what a powerful ally Nico could potentially be for him, as he claims to see a decent amount of ruthlessness in the son of Hades, which he also greatly appreciates. Hence, Octavian promptly attempts to sway the son of Hades to his side, arguing that the Greeks hadn't ever actually done anything for the former. Octavian claims that he can beat any offer the Greeks might have given Nico, and assures him a place in New Rome in return for Nico siding with him and allowing the Romans to win. Nico, however, doesn't even consider the offer, declines right away, and promptly tells all of the assembled demigods to listen to what Reyna has to say, just as she arrives with the Athena Parthenos in tow. Nico is later present when Octavian intends to shoot an onager at Gaea, and clearly sees that doing so will result in Octavian's death. However, it is at that moment that Nico recalls what his father Hades had told him, about some deaths that cannot and should not be prevented, and Nico needing to act when the time comes. Hence, for the first time, Nico decides to trust the wisdom of his father, and stops Will (who stares at him in disbelief) from trying to prevent Octavian's plan, and subsequently witnesses the augur's horrific fiery demise, along with the death of Leo and destruction of Gaea. While Nico isn't at all saddened by Octavian's death, he is very guilt-ridden, since Nico feels that him choosing not to prevent Octavian's death unnecessarily cost Leo his life, something that he is unable to forgive himself for. Nico is also horrified of Will now possibly thinking of him as a monster for letting Octavian die, but is extremely relieved to learn of that not being the case.
In The Sun and the Star: A Nico di Angelo Adventure, when Will accuses Nico of not caring about his role in Octavian's death, Nico admits that he thinks about it all the time. Later, the cacodemon that Nyx makes out of Nico's guilt shows him visions of Octavian's death, showing that Nico truly still feels guilty about what he did.
====Hunters of Artemis====
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Nico does not care for Artemis' immortal handmaidens, since his sister died shortly after joining. He feels that the girls who do join should be more aware of what they are getting themselves into, as well as just forgetting about his sister when she died shortly after joining. When the Son of Hades awoke in San Juan and saw the note they left, he tore it up in a fit of rage. Despite fighting alongside Thalia before, he still has mixed feelings for her, mainly because she is the lieutenant of Artemis and continued recruiting after Bianca died.
====Thalia Grace====
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Nico has a neutral opinion of Thalia as the son of Hades has had little interactions with the daughter of Zeus. On their first encounter after his sister’s death, Thalia referred to him as “Bianca's brother”, annoying him. They two worked well together as they looked for his father’s sword. 
Upon meeting up in San Juan, the son of Hades aided her and the other Hunters of Artemis, despite his hatred of the group, in fighting Orion.
==Etymology== 
*Nico is the diminutive form of Nicolò or Nicola, the Italian form of the Greek Nikolaos (Nicholas), meaning "victory of the people." It is most likely intended to evoke the prefix necro-, meaning dead.
*di Angelo is Italian for "of [the] angel".
*The full meaning of his name would thus be "angel of the dead", alluding to his role as the Lord of the Dead's son.
*Nico is also a form of the Greek Nike, meaning "victory".
==Trivia==
*The line "With great power . . . comes great need to take a nap." is an obvious reference to one of Spider-Man's most famous lines: "With great power, comes great responsibility", albeit a bit altered for comedic effect and to indicate that Nico's powers tire him greatly, prompting him to take naps every now and again to regain his strength, as he did at that moment in The Last Olympian.
*Nico has many similarities to Anubis, the Egyptian god of funerals.
**They share the same nickname: "Death Boy".
**Nico's physical description (pale olive skin, dark hair, black eyes, black clothes, and an aura of death) also fits Rick Riordan's description of Anubis, the Egyptian god of funerals, in The Kane Chronicles trilogy.
*The first time he met Mr. D, he called him "The Wine Dude", which irritated the god, but he forgot about it soon after as Nico complimented him.
*Nico has been shown to be a solitary type of person, but he has a certain way of communicating with people. He was the first demigod in years to notice the goddess Hestia and speak with her, he persuaded his father Hades to fight in the Titan War when no one else could, and he alone convinced the Titan Bob to save Percy and Annabeth.
*Nico has been to a New Orleans graveyard, though it is unknown why he went. Interestingly, this is one of the favorite hangouts of Anubis. It was also the place that his half-sister Hazel Levesque lived just before her death.
*Nico and Jason Grace have similarities:
**They both have older sisters, whom have both been/are Hunters of Artemis.
**They have both been to Camp Half-Blood and Camp Jupiter.
**They have godly stepmothers (Persephone, Juno).
**Both have lost their memory. Nico's because of being dipped in the River Lethe and Jason's was removed by Juno although Jason's is temporary.
**Both are powerful and respected demigods.
**Both are children of the Big Three gods.
*In The House of Hades and The Sun and the Star: A Nico di Angelo Adventure, it's shown that Nico has recovered at least some of his lost memories from before his dip in the River Lethe, including one of when he was eight and living in Italy. 
**Although unconfirmed, this may have to do with Nico drinking from the River Phlegethon while traveling through Tartarus as the river has a healing effect on demigods and Nico drank from it multiple times with Nico being unsure of any long-term ramifications of drinking from the Phlegethon.
*Hazel Levesque and Nico's mothers share similar first names: Marie Levesque and Maria di Angelo.
*Nico's birthday is undecided. Rick Riordan has stated on three different occasions his birth-date: January 28th, 1924, May 16th, 1924, and October 31st, 1924. 
**However, the year would be way off since in The Son of Neptune, Hazel stated he was only a few years younger than her. Another contradiction comes from The House of Hades where in Nico mentioned that he was about six years old when he first visited Diocletian's private residence in "[nineteen] thirty-eight or so". This would put his date of birth at around the early 1930's.The House of Hades, page 272
*In the series, he is described as having long, shaggy black hair, but in his earlier portrait he has short brown hair. Also, he seems to have green eyes instead of brown, and not as pale of skin. A more recent portrait shows a more accurate image of him to the story.
*Unlike his half-sister Hazel, horses don't like Nico (as Porkpie, one of Blackjack's friend once stated: "He smells like dead people.")
*Most animals don't like Nico due to him smelling like death, and the feeling is often mutual.
*Nico has the ability to control ghosts. However, Melinoe is the goddess of ghosts, not Hades.
*Prior to Camp Half-Blood Confidential, Nico was supposedly the only person who had ever seen Camp Half-Blood's Orientation Film. Unlike the others, for which the film was "traumatizing", Nico enjoyed it, calling it "awesome." (Also noting in Camp Half-Blood Confidential, his decision has changed as he was discussing with Percy what changes they would make if they ran the camp and he mentioned ‘the first thing I’d do is make sure the poor newbie demigods don’t have to suffer through the orientation film.’)
*As of The Last Olympian, Nico is the first demigod in many years known to have stopped by and spoken to Hestia, who is usually ignored when she visits Camp Half-Blood.
*As of The Son of Neptune, Nico is the first known Greek demigod since the First Demigod Civil War to learn about the existence of Roman demigods and to visit Camp Jupiter.
*Nico is the only known Senator at Camp Jupiter that was neither a Centurion nor a Praetor, instead serving as the Ambassador of Pluto.
*As of The Mark of Athena, Nico is the first known demigod ever to have returned from Tartarus alive, but even as a son of Hades, his stay in Tartarus left him shattered, irascible, and even more withdrawn than usual. 
**Percy speculates when on the verge of death and seeing Tartarus as it really is, that Nico had seen it that way the whole time, and that even a few moments of seeing, it was maddening. He wonders how Nico had survived with his sanity. Nico himself stated it nearly drove him insane. As revealed in The Sun and the Star: A Nico di Angelo Adventure, a lot of this had to do with Nico seeing the Mansion of Night for what it truly is.
*As of The House of Hades, Nico is the only known demigod that Leo and Frank are afraid of. They eventually get over that fear.
*Nico has been transformed into plants twice in the series: into a dandelion by Persephone during a "family spat" shortly before The Demigod Files, and into a corn plant by Triptolemus in The House of Hades.
*Nico is the first confirmed LGBTQ+ demigod (with Will Solace and Alex Fierro being later confirmed to be as well, in The Hidden Oracle and The Hammer of Thor respectively, and not counting the asexual Hunters of Artemis), something he has been trying to hide for years. The only blatant clue is in The Titan's Curse when he asks Percy if Annabeth is his girlfriend. Jason believes that Nico's hiding of this has to do with Nico being from the 1940s, where homosexuality wasn't accepted.
**Hence, as of The Hidden Oracle, Nico and Will are the first gay couple shown in the series.
**In The Sun and the Star: A Nico di Angelo Adventure, Nico reveals that when he was eight and living in Italy, he experienced homophobia from a friend of his, leading to Nico's fears.
*In both the Percy Jackson and the Olympians and the The Heroes of Olympus series, Nico ensures the fulfillment of the Great Prophecies: Nico helps Percy gain the Curse of Achilles, which enables both Percy and Luke to defeat Kronos ("the hero's soul cursed blade shall reap"), and Nico tells Iapetus that Percy is a friend, which induces him to follow Percy and Annabeth to the Doors of Death ("foes bear arms to the Doors of Death").
*Hades once gave Nico a French zombie chauffeur, Jules-Albert, for his birthday.
*When he was little (even before he became interested in Mythomagic), Nico was obsessed with pirates.
*Nico is mentioned in the Lightning Thief Musical by Bianca Di Angelo.
*As mentioned in The Tower of Nero, Nico was raised Catholic and Conservative.
*As of The Tower of Nero, Nico is confirmed to have Post Traumatic Stress Disorder, or PTSD. This also makes Nico the first character in the Percy Jackson Universe to have a mental disorder outside of ADHD and Dyslexia.
**In addition to PTSD, Will says "... Nico doesn't eat very much these days", which may imply that Nico, could have some kind of eating disorder.
*Nico is described as smelling like rain against a stone. Porkpie said Nico smells like death which is why he doesn't want to ride with him.
*Nico has taken part in the final battle of each of the last books of the Camp Half-Blood series.
*The character of Filomena di Angelo, in The Last Hours trilogy by Cassandra Clare was named after him.
*Nico is the first known demigod to "father" children with a primordial being in this case being Nyx, albeit without Nico's knowledge.
*In an interview, Rick Riordan described Nico and Will as "soulmates of equal brightness, no matter how different or far away they seem from one another."https://www.themarysue.com/rick-riordan-mark-oshiro-percy-jackson-spinoff-the-sun-and-the-star-interview/
==References==
Category:Greek Demigods
Category:Males
Category:LGBTQ+ Characters