Kyojuro Rengoku/Synopsis

The story of the Flame Hashira Kyojuro Rengoku from Demon Slayer: Kimetsu no Yaiba.
==Past==
====Childhood====
Kyojuro Rengoku was born as the son of Shinjuro and Ruka Rengoku. His father was a member of the Demon Slayer Corps, serving as the Flame Hashira. During his youth, he was trained by his father on how to wield a sword. He later became the elder brother of Senjuro. Unfortunately for the Rengoku Family, Ruka was plagued with an untreatable disease and she died shortly after. Before dying, Ruka instilled a moral code within Kyojuro to use his strength to help the weak, a lesson he took to heart for the rest of his life.
Due to the mixture of losing his wife and the disillusionment after discovering Hinokami Kagura and its superiority to all other breathing styles, he became abusive and neglectful to both of his sons, while becoming an alcoholic mess. Meanwhile, Kyojuro had a close bond with his younger brother, and even encouraged him to pursue his desire for swordsmanship, despite lacking the talent to do so. And even with his father's abuse, Kyojuro still loved him and cared for his well-being. 
====Kyojuro Rengoku Gaidan====
Some time later, Kyojuro would become a Kinoe-ranked Demon Slayer. It was noted that Kyojuro managed to learn Flame Breathing by reading a guide book of Flame Breathing, a book which only had three volumes. He would also become the mentor of a young woman by the name of Mitsuri Kanroji, who joined the slayer corps in hopes of finding a strong man to be married to and be accepted, due to her unique strength and flexibility. However, during their training, it was discovered that Mitsuri couldn't use Flame Breathing properly, so she instead altered it and created her own personal Breathing Style known as Love Breathing. The training between Rengoku and Mitsuri would eventually create a strong sibling-like bond between them, as Mitsuri views Rengoku as her big brother. 
Six months later after Mitsuri passes the Final Selection, Kyojuro still continues sparring with the young woman, noting that she has gotten weaker. Mitsuri replies the reason why is because she is hungry and asks for a break, although Kyojuro noted that they had lunch recently, urging her to continue her spar training. Senjuro then appears, having made some food for them, causing Mitsuri to tackle the boy in a hug. Kyojuro beckons Mitsuri to continuing training, but he eventually decides that a break is due. As the two enjoys Senjuro's food, Mitsuri's uniform arrives for her, something that Kyojuro praises Mitsuri for, acknowledging her no longer as a student, but now a partner, much to her immense joy. As Mitsuri puts on her new uniform, Kyojuro is gravely shocked to see that the uniform reveals her chest. When he asks if it is meant to be a tighter uniform, she mentions that the Kakushi who made it (Masao Maeda) said it was the official style. Though doubtful and flustered by this, Kyojuro accepts it. 
==Demon Slayer: Kimetsu no Yaiba==
===Hashira Meeting===
Kyojuro, along with the rest of the Hashira, was summoned to the Demon Slayer Headquarters for the semi-annual Hashira meeting and to enact a trial. The suspects in question were Tanjirō Kamado and Nezuko Kamado, the former of which was a Demon Slayer who had protected his demon sister (Nezuko) in clear violation of the Corp's code. The Water Hashira Giyu Tomioka was also guilty of the same crime, although his penalty was set to be decided at a later date.
While Shinobu Kochō wanted to understand the reasoning behind Tanjiro's violation of the code, Rengoku, and a majority of the Hashira, simply wanted to execute Tanjiro, and his sister on the spot. He respectfully voiced his disdain when Ubuyashiki decided to sanction Tanjiro's situation, and was shocked when the master revealed that Tanjiro had met Muzan Kibutsuji himself. Kyojuro watched on as Sanemi Shinazugawa attempted to coax Nezuko into consuming his nutrient-rich blood, and later admired Tanjiro for ambitiously claiming that he would defeat Kibutsuji.In the evening after the trial, Kyojuro attended the Hashira Meeting. Ubuyashiki and the Hashira mostly discussed the potency of new recruits and the plans of Kibutsuji. Kyojuro expressed pride/hope towards Kamado for his encounter with Lower Five and that he desired to kill more of the Twelve Kizuki.
The night after the meeting, Kyojuro received word that a demon had devoured over forty people on a train and that any Slayer that was dispatched met the same fate. Believing that the demon in question could be a member of the Twelve Kizuki, Kyojuro left Headquarters to deal with the threat.
===The Mugen Train Arc===
====The Train Attack====
It turns out that there is indeed a member of Twelve Kizuki named Enmu, the strongest of the Lower Moon batch with the ability to hypnotize people and manipulate dreams. The said demon struck, putting all passengers aboard while the train is running using Blood Demon Art. During the spell, four people under Enmu's employment attempted to infiltrate into Kyojuro's group's dreams and destroy their spiritual cores. When the girl managed to find Rengoku's core, in his subconsciousness, he may seem to be aware of what was going on as he thwarts the girl by nearly suffocating the girl in self-defense. Other hirelings of Enmu also failed to destroy the spiritual cores of Kyojuro's group.
In scenes exclusive to Mugen Train, inside his dream, Kyojuro defended the passengers from a twin-faced and multi-armed demon that made attempts to kill them before taking them down one by one alongside Tanjiro and the rest.
After waking up to discover the entire train taken over by Enmu and with Tanjiro already attempting to defeat Enmu, he asks him to go to the main part of the train that locates Enmu's neck while he goes from cart to cart protecting the passengers as he slashes away Enmu's embodied parts around the train alongside Zenitsu, Inosuke and Nezuko. While Tanjiro was doing this, Kyojuro fended off Enmu attempting to feed on passengers and defended the multiple sections of the train whereas Inosuke and Zenitsu were struggling to defend just one section of the train.
After Enmu's defeat and demise, he helps wounded Tanjiro to prevent his abdomen from bleeding by using his Total Concentration Breathing as he began explaining to him that he'll be able to achieve anything by tomorrow as he will grow stronger and doesn't need to force it.
====Vs. Akaza ====
That was when the Upper Moon Threee, Akaza, appears out of the blue. Akaza, intending to kill Tanjiro (as was his mission), swoops down on the wounded demon hunter, but Kyojuro fends Akaza off in a nick of time. Akaza, realizing how strong Kyojuro is, offers Kyojuro to join the Twelve Demon Moons but the Flame Pillar declines, before or while fighting within their battle, they both began explaining their own respective views on life, Akaza is shown to hate humans for being weak while Rengoku began telling him that humanity has more to its beauty than just strength alone as the battle continues on. Tanjiro, Zenitsu and Inosuke, in addition to being ordered by Kyojuro to be on standby, could only watch their battle as they knew they could become hindrances to Kyojuro.
Given how immensely strong Akaza is, Rengoku was still getting more determined to get up to fulfill his duties of protecting others around him. However, as mighty Kyojuro was, he is but a man whereas Akaza is a demon; as the fight dragged on, Kyojuro becomes increasingly more tired and received more wounds each injury heavier than the last, while Akaza heals every wound he gets inflicted by Kyojuro. Even if Akaza still tried to convince him to become a demon after his body is in too terrible a condition to go on fighting, Rengoku still refuses as he made his move to fully unleash the ultimate Flame Breathing technique just as Akaza unleashed his own powerful Blood Demon Art technique. 
However, Akaza comes out triumphant by impaling Kyojuro's stomach, resulting in a huge wound that made him lose enormous amounts of blood, virtually sealing Kyojuro's fate. While that happened, he began remembering his mother during their final moments together before her passing. Before death, she cries and tells her son he was such a blessing a mother could ever ask for.
Back to the present, Akaza, meanwhile, begs Kyojuro to give up being stubborn and insisting on going on as a weak human instead of becoming a demon. Kyojuro, began using what's left in his strength to swing his Nichirin Blade to cut open Akaza's neck as the latter attempts to punch him for the blowing kill before blocking it, the finishing end didn't last when the sun rises as Akaza attempts to make his leave. Rengoku pulls his hardest, determined to hold Akaza as he plans to sacrifice himself with him. But as Inosuke tries to ready his First Fang - Pierce, Akaza manages to escape by severing his own arms. But as Akaza flees, the Upper Moon 3 demon is stabbed in the throat by Tanjiro's sword, the young slayer screams and calls him out for being a coward that ran away from a fight as he implies Rengoku won and he lost, thus meaning his fight with Akaza was to protect everyone back from the train. Having failed to kill what he came for and be mocked by his prey, Akaza was forced to retreat in disgrace as the sun rose to become morning.
====Death ====
During his final moments with Tanjiro and Inosuke, Kyojuro tells them that there are notes left saying about Hinokami Kagura and other things regarding the answers he needed, saying he is welcome to visit his home. He stats to Tanjiro that he is too weak to use his Breathing technique to heal the wound given by Akaza which was too severe to be healed by human means anyway as he accepts his impending fate. Realizing he has not much time left, Kyojuro says a few words to Tanjiro about telling his younger brother Senjuro and his father the many things he wanted to say to them and how he truly accepts Nezuko for her actions as he thinks of her as a member worthy of the Demon Slayer Corps. Then what came next was him saying to Tanjiro that he shouldn't continue mourning for him as it was natural for a Hashira to protect his or her junior, he uses his final words to Tanjiro that he, Zenitsu, and Inosuke will become the future for their generation as his encouragement to them.
Before he dies, he sees his mother Ruka Rengoku in a vision as he asks her if he did everything right, she says she was proud of what he did. Kyojuro smiles for one last time, before being finally expired.
===Aftermath and Legacy===
News of Kyojuro having fallen in the line of duty came as shock and sadness to Demon Slayer Corps, with the following members in particular having their own reactions:
*While grieving, Tanjiro Kamado was frustrated that he overcame one obstacle to become stronger, only to run into even bigger and harder obstacle standing before him. Inosuke Hashibira berates Tanjiro and Zenitsu Agatsuma not to grieve Kyojuro's death, declaring that he had merely returned to earth and all they can do is to fulfill the promise they made with Kyojuro by continue surviving and go on living. But as Zenitsu pointed out, Inosuke was grieving just as much as Tanjiro.
*Shinobu Kocho was sadden to hear about his death, while Kanao Tsuyuri was surprised.
*Tengen Uzui laments that someone as powerful as Kyojuro was no match for an Upper Moon demon.
*Mitsuri Kanroji was horrified (which is understandable, considering she was his tsuguko).
*Obanai Iguro refused to believe the obvious until he would see with is own eyes.
*Gyomei Himejima prayed for Kyojuro's soul.
*Sanemi Shinazugawa steeled himself to eradicate demons.
*Kagaya Ubuyashiki praised Kyojuro for his gallantry and sacrifice, stating that he too, does not have long and would join the deceased Flame Pillar in the afterlife.
Senjuro reacted with grief when the news reached him of his older brother's death. However, when Tanjiro visited the Rengoku household to read the notes Shinjuro kept, the jaded former Hashira drunkenly insulted his deceased son and claimed that his death was due to a lack of worth and talent. After a physical altercation with the boy (who was angered by his abuse towards Senjuro and his ill words towards Kyojuro), Shinjuro was given his elder son's final words to him by Senjuro, telling him to take care of himself. Not being able to hide behind his wall of denial and apathy anymore, Shinjuro broke down in tears, a starting point for the man to finally turn his life around.
But as the series moves on, Tanjiro still remembers Rengoku with all of his heart as his encouragement and notes left to Tanjiro, who will make it his promise, will help him succeed in ending Muzan Kibutsuji's expansion of the Demon race once and for all for the greater good. In addition, Majority of his comrades remained fond of him, and remember the influence he had on them, such as Tengen (who stated he could never be like Kyojuro) and Muichiro (who remembered the time he spent with Kyojuro).
Kyojuro's death would later be avenged after Tanjiro and Giyu killed Akaza during the Infinity Castle battle. When Tanjiro temporarily became a demon by Muzan as a last attempt to create his own legacy, Kyojuro's soul was one of the departed that helped save Tanjiro's humanity.
Category:Synopsis