Aritoshi Reiroukan

is the Master of Caster in the First Holy Grail War of Fate/Prototype: Fragments of Sky Silver. He is the patriarch of the Reiroukan family and father of Misaya Reiroukan.
==Profile==
===Background===
In the Holy Grail War of 1991, he is the current family head of the Reiroukan family. His family includes his wife and only daughter, Misaya.
Being from one of the elite Magus families in the east, Aritoshi and his family maintain many connections with politicians, leaders and businessmen causing them to have a lot of pull with local governments.
===Appearance===
Aritoshi's appearance is not heavily mentioned or shown in the novels.
===Personality===
He is a very influential character, having ties to political figures. He is also very trusting. He loves his daughter Misaya and his family very much.
==Role==
===Fate/Prototype: Fragments of Sky Silver===
In December 1990, Aritoshi is giving Misaya Magecraft lessons. After praising her, Aritoshi expresses his gratitude to Misaya for being born, which slightly unnerves her. Getting serious, he then informs Misaya that he is participating in the Holy Grail War and that he has decided to let her stay in the manor during this period, instead of sending her off with her mother to their villa in Izu. 
====Day 1 - Summoning Caster====
Two months later, Aritoshi summons Caster with some gems. After getting acquainted, Aritoshi asks Caster to become his daughter's friend. Caster agrees. He then shows Caster to his workshop and asks for his help in enforcing the manor's Bounded Fields over the next few days.
====Day 4 - Introductions====
On day four, Aritoshi summons Misaya to his office and introduces her to Caster. That night, Berserker makes an attempt on the manor, but is forced to withdraw due to strength of the manor defenses. At the same time, Aritoshi makes arrangements for a meeting with the Rider camp to form an alliance with them. 
====Day 5 - Meeting with Rider====
On the evening of the fifth day, Aritoshi is alerted to the presence of Rider outside the main entrance by Caster and welcomes him inside. After some rude greetings, Aritoshi and Rider get down to business and sign a self-geas scroll as a sign of their alliance. 
After their business is done, Rider and Aritoshi sit down for tea while Caster cautiously watches him. Caster remarks that Rider seems confident in his abilities and Rider asks if the same goes for him. Caster replies that he is halfway there, making Rider laugh. Rider then alerts the group to a spy (a curious Misaya) spying on them through the window using her bird Familiar. 
Delighted by Misaya's audacity, Rider announces his own agreement to the alliance and starts jinxing her through her Familiar. Remarking that Rider is a terrifying person, Caster asks Rider what he was going to do if he hadn't agreed to the alliance. Rider responds that he was naturally going to kill them. Rider then releases his spell on Misaya and leaves.
====Day 6 - Conversation With Manaka Sajyou====
The next night, Caster meets with his Master and asks him if he is alright with the previous day's events. Aritoshi says it is fine, but laments on the methods he had to take. Caster agrees and asks if he really needed to sign a Self-geas Scroll, but Aritoshi remarks that it is a necessary risk. Ending the conversation, Caster announces he is heading to the basement to check on the spiritual barriers and goes to leave.
However, before Caster can leave, Aritoshi calls out to him and asks about the tear in the barrier he had noticed last night. Caster lies and declares that it was probably Berserker's fault. He then apologizes for not reporting it sooner. Master Reiroukan remarks that it is fine, but cautions him to make sure it is fixed. He then compliments Caster's barriers and lets Caster leave.
After Caster leaves, Aritoshi opens a letter from the Sajyou family presuming it is Hiroki contacting him, only to be surprised that it is from Manaka. In the magical video message, Manaka greets Aritoshi and introduces herself to him. Manaka continues that she has something to tell him and informs about what she discussed with Saber about exploiting the other Masters' weak-points. Manaka asks for Aritoshi's opinion on this and uses Misaya as an example. Manaka continues to explain that if Misaya were to disappear, it would be very hard and painful for him.
Aritoshi immediately becomes furious by this. Manaka then comes to the terms of their partnership. She will take the Greater Grail (Saint Graph) and in exchange Aritoshi will protect the Lesser Grail (Symbol) for her. Master Reiroukan gets upset and is shocked that Manaka knows about its whereabouts. Aritoshi then asks himself about how much she knows about the Greater Grail and its history. Giggling, Manaka then says her goodbyes as Aritoshi yells out cursing Manaka's name.
====Day 8 - Attack on Misaya====
Around one a.m on the eighth morning of the Holy Grail War, Aritoshi becomes alerted to Berserker's presence again. However, when he checks their surveillance network, he discovers Misaya being attacked by Berserker. After Misaya is rescued by Saber, a panicked Aritoshi greets her. Asking her if Saber's Master was with her, he becomes relieved when she said she didn't see them. Later in his office Aritoshi scolds her for her recklessness. He then forbids her from leaving the manor at night and tells her to go to bed.
After she leaves, Caster relays his concerns for Misaya’s safety and Aritoshi replies that the extra measures are to protect Misaya from Manaka, who he has deemed to be a threat. Caster then alerts Aritoshi to an intruder. However, Aritoshi tells him that it is alright as it is an emissary from the Holy Church. Aritoshi then goes to welcome his guest. 
That night, Master Reiroukan watches the battle between Berserker and the rest of the Servants. He then watches as Berseker is incinerated by Rider. Around this time, he notices traces of a curse on Misaya and becomes concerned.
====Day 9 - Searching for a Cure====
On the night of the ninth day, Aritoshi is hastily ruffling through his workshop looking for the curse stone to find a cure for Misaya’s curse. As he does so, he thinks on Manaka and wonders how she managed to curse Misaya. Meanwhile, Caster reports to Manaka that he has finished placing the curse on Misaya and that it can be activated at any time.
====Day 10 - Betrayal and Death====
On the tenth night of the Holy Grail War, Aritoshi confronts Caster and Manaka in their back garden. Asking Caster if he has betrayed him, Caster confesses that he has. Suddenly, Aritoshi keels over in pain and realizes that he is suffering the effects of a "Geas annulment" as Caster had betrayed Rider by siding with Manaka. Manaka informs Caster about the current situation on Tokyo Bay. Offering to kill the Isemis for her, Manaka tells Caster that it is fine as she will head to the Okutama mountains workshop with Assassin to eliminate the Isemi.
Angry, Aritoshi admits that he is disappointed with Caster and angrily asks why he had cursed Misaya. Caster doesn't answer. Manaka intervenes and reveals that she was intimidated by Rider. She then sarcastically tries to cheer Aritoshi up by gushing about Saber. Thinking to himself, Aritoshi tries to find a chance to attack Manaka. However, he is impeded by the Geas he made with Rider. Using his Master Degree, Aritoshi tries to order Caster to kill Manaka. However, he is stopped by Manaka who uses paralyzing Magecraft before he can finish his order. Getting up close to him, Manaka then informs Aritoshi that she will now finish the curse that Caster had placed on Misaya.
After Manaka activates the curse on Misaya, Aritoshi somehow escapes and makes it to Misaya's room. Bursting in, he awakens her and startles her with his appearance. Fighting the pain, Aritoshi collapses on the floor. As Misaya runs over to him, he warns Misaya about Caster's betrayal and explains that a fatal curse has been put on her. He then explains that she will need the Holy Grail to cure that curse. As Misaya cries for him, he apologizes and stabs her with a knife Mystic Code to channel suppression Magecraft to hold back her curse. Aritoshi then dies. The next morning, Misaya wakes up and discovers her father's corpse in their main courtyard.
==Abilities==
The Master of Caster utilizes Rune Magecraft, Necromancy, and General Black Magic. He also dabbles in Alchemy. 
==Development==
Unnamed, only called , and without a character design in the novels, material books, and drama CD materials, Aritoshi was first given a design and name for the manga adaptation.
==References==
Category:Magi
Category:Masters
Category:Characters in Fate/Prototype: Fragments
Category:Heads of household
Category:Humans
Category:Introduced in 2014
Category:Japanese