|“||Nah, it's fine. I'm kind of a demon. But if there were real demons beside me, I'd like to try to talk a little with them. Now that'd be nice.||„|
|~ Ryuunosuke Uryuu|
Ryuunosuke Uryuu is a major antagonist from the light novel and anime series Fate/Zero. He is a serial killer and the Master of Caster during the Fourth Holy Grail War. Unlike the other Masters, however, he has no interest whatsoever in obtaining the Grail and merely wishes to use Caster as a tool for his killing spree. He serves as the main antagonist of the first season of the anime (as well as the corresponding novels).
He is voiced by Akira Ishida in the Japanese version of the anime and Johnny Yong Bosch in the English version.
Ryuunosuke is a serial killer. While searching for different, more "amusing" ways to commit murder, he finds a book at his parents' house with instructions on how to summon a Servant. Even though he is not a magus, he was selected by the Holy Grail to fulfill the war's requirement for seven Masters and seven Servants. However, he knows nothing of the Holy Grail War; his involvement in the war is mainly to watch his servant Caster kill people in unique and thrilling ways.
Ryuunosuke is to put it simply obsessed with the process of death and dying. He believes that humans are inherently curious in death similarly to a sort of forbidden knowledge and try to understand it by observing other people's death while making up a virtual experience, which is why he became a murderer.
According to him, beliefs about depiction of cruelty in fiction having been a bad influence on young people are ridiculous nonsense, because he wouldn't have become a homicidal maniac had it been for blood and screams in horror being a little more realistic. He satisfies himself by squeezing the best out of the life force of those he kills, and of feelings such as the attachment of human life, anger, and affection. To let his victims know the exact time and circumstance of their death, that in itself had a deep meaning as rich as miniaturized life, and the more people he killed, the more he understood the lives he took. He considered that knowledge and that discernment in itself, which was a kind of dignity and a style in his distorted logic, as something "cool."
His characteristics as a serial killer are radically different than the typical psychopath as he is a very malicious and emotional man simply thrilled with brutality of his crimes. His impulses are so strong, it almost seems like he exists in his own little world as he hardly acknowledges the existence of people outside himself. This manifests in a lack of consideration of what he says amongst others, and his charm seems almost insane in his radical mood swings and treatment of others.
Ryuunosuke primarily aims to murder young women and children, mainly because they're easy targets for his sadism. The innocence and lack of self-defense that characterizes his victims makes his crimes all the more cruel and exciting through his eyes since they have little to no chance of escaping. Prior to his involvement with Caster, he would invade other houses and kill the inhabitants when he had the opportunity. Ryuunosuke has no knowledge about the magecraft world and his involvement in the war is simply to watch Caster butcher people in unique and thrilling ways. Afterwards, he gained a bracelet allowing for hypnotism that made kidnapping people far easier, and began to use it so he could bring children to their lair. Caster's ability to extend the life-span of humans came as a great blessing to Ryuunosuke, for he could inflict far more serious damage to his victims with no fear of them perishing. This allowed for greater experimentation and the creation of art out of his victims bodies. Ryuunosuke crafts furniture, instruments, and atmospheric creations such as crucified corpses within their lair that made killing a more unique experience.
Apparently, Ryuunosuke revels in seeing death, but has no preference in whether he is the cause. When Caster summoned his abomination, Ryuunosuke was overjoyed because he no longer had to risk anything or go out of his way to kill people, for he thought the monster would do all the killing for him. This is quite odd for someone constantly vying for new sensations, but given his positive nature, it's also thoughtful characteristic.
His last thoughts were the brightness and vibrance of his lifeblood and the excitement as he experienced his own death.
Ryuunosuke's personal relationship is with his Servant Caster, whom he likes to watch kill others in amusing ways. The two of them are rather fond of each other, and thus are considered partners in crime. In fact, out of all the Master/Servant relationship in the entire Fate franchise they have the best one which is ironic as they expected each other the least. This is in stark contrast of the other more heroic servants (ex. Kiritsugu Emiya and Saber) whose ideals that clash too much to the point where they are basically incompatible for one another.
Shortly before the beginning of the Holy Grail War, Uryuu Ryuunosuke discovers a spell book in his parents house that he mistakenly believes is to be used for summoning demons. With the tome's guidance, he kills several families throughout Fuyuki and uses their blood to create the servant summoning circle. On the day the Holy Grail War is set to begin, he murders an entire family with magical potential, except a young boy and performs the ritual as outlined in the book.
Though he made several mistakes in the process, the Holy Grail accepts his effort and he receives the final servant class available, Caster. Unfortunately, as he was so inexperienced and did not have a catalyst, the Holy Grail simply picked a servant that had a similar personality to Ryuunosuke. This hero was Gilles de Rais, who was a comrade in arms of Jeanne d'Arc and a prolific child serial killer. After their contract is sealed, Ryuunosuke offers the still-living boy to Caster as a sacrifice. He grows excited as Caster pulls out Prelati's Spellbook, charmed by its cover of flesh, but is disappointed to see Caster is letting the boy go. Caster tells him not to complain however, and as the boy attempts to exit the house, he's pulled away by a mysterious creature that brutally murders him. When the screaming dies down, Caster explains his philosophy to Ryuunosuke that terror is a dynamic state in which you can extract the most despair from a victim by giving them hope and quickly crushing it.
This enthralls Ryuunosuke, who devotes himself to being Caster's follower should he show him cooler ways to kill people. Overjoyed to have received such an understanding master, Caster grips his hand and speaks about how it feels that his dream is almost in his grasp. He then introduces himself to Ryuunosuke as "Bluebeard", a character based on Gilles de Rais himself.
For the next few days, Caster and Ryuunosuke take to locating a lair in the sewers below Fuyuki and studying the art of murder. Eventually Caster is able to utilize a crystal ball to spy on the other masters and servants, and mistakes Saber for Jeanne. He approaches her and attempts to have Saber become his ally, but believes she has gone insane and forgotten her identity when she is confused by his behavior. He returns to Ryuunosuke and decides that they will change their work from torture on a few individuals to killing as many people as possible to have God release his grip on Saber's mind, much to Ryuunosuke's disapproval.
As the story continues and it's made apparent that Caster and his master are only targeting innocent people, Risei Kotomine informs all active masters that the Holy Grail War is to be "put on hold" until Caster is eliminated. The master who kills him will also receive an extra command spell, but this is somewhat of a ploy for Tokiomi and Risei plan to have Archer perform the deed. Caster then makes an appearance in the Einzbern forest with numerous children in tow, and proclaims that he will murder each one until Saber comes to meet him. By the time she has arrived, Caster has killed them and gathered their corpses, and using his noble phantasm, uses their flesh to summon constantly-regenerating monsters. Things look dire, but when Lancer shows up to aid in Saber's plight, he lands a blow on Caster's spell-book and eliminates his familiars. Defeated, Caster quickly retreats back to continue his killings with Ryuunosuke.
Around this time, Waver uses a technique of studying mana in the Fuyuki river to locate Caster's lair, which he and Rider promptly invade. When they arrive, they find nothing but the dozens of victims they murdered, and Kirei's Assassins who came to kill Ryuunosuke. They dispatch the Assassins with ease, but disgusted with the atrocities before them, burn the corpses that remain.
Not deterred by the manhunt, they keep on hunting down children and causing fear throughout the community. However, Rin Tohsaka begins to investigate when one of her friends from school goes missing. She finds that Ryuunosuke is using an enchanted bracelet to hypnotize children and bring them to his lair. When she finds her friend in a comatose state, Ryuunosuke approaches her with a friendly attitude. He asks her if she wants to be involved in the "party" he's planning, but she refuses and attempts to escape. She grabs onto Ryuunosuke's arm and tries to destroy his bracelet, but it nearly grips her mind before she can overload it with mana and cause it to explode. This releases the children from their zombification and they quickly run away, with Ryuunosuke remarking that he hopes Caster won't be mad.
(In the Light Novel, Rin never reaches Ryuunosuke's lair because she is blocked by one of Caster's abominations before being saved by Kariya. Because of this, it can be assumed that his victims were all murdered and only spared for the anime adaption.)
When Caster and Ryuunosuke return to their lair, they find it destroyed by Rider's fire. In complete despair for having his artwork ruined, Ryuunosuke begins to cry while Caster tells him about how cruel life is to people of their villainous preference. Caster is surprised though, when he's asked about the existence of God, as he didn't believe his master to be spiritual. Ryuunosuke then shares his philosophy that God must be somewhat malicious to make the world with them in it, as he believes that God likely enjoys displays of violence, gore and evil actions. This firmly wins Caster over, as he hails Ryuunosuke as a brilliant philosopher and they resolve to perform a grand spectacle to amuse God.
Caster's plan is revealed to be the summoning of his ultimate weapon, a gigantic, tentacled monster out of the Fuyuki river which he describes as the greatest "cool". As the creature begins to emerge, Ryuunosuke becomes more and more excited to see other servants come to challenge it and fail due to its constant regeneration, and how it swallowed a fighter jet with ease. Ryuunosuke begins a monologue in which he states that he is happy he won't have to go out of his way to commit murders anymore, as he can just watch Caster's monsters do it for him in so many thrilling ways. When he screams up to the heavens happily, he is suddenly hit by something and falls to the ground. The other people around him look at him with fear as he realizes that he was hit in the stomach by a bullet. It is revealed that Kiritsugu was using an infrared scope to see people's body-heat, and detects Ryuunosuke to be Caster's master due to having excessive heat which displays the release of mana.
This new occurrence does not cause him unease however, as he acknowledges how beautiful his own blood is. Since he is been anticipating death his entire life, he is relieved that its better than he expected. His grand finale came at last, and he realizes that there's no greater pleasure for him in life than to experience his own passing. He is then shot in the head by Kiritsugu who realized he was Caster's master by the abomination's sudden halt, and dies with a smile upon his face.
Uryuu Ryuunosuke is not a magus, but he is descended from a lineage that once resided in Fuyuki. Using notes left behind by his ancestors, he summons Caster by creating a summoning circle as outlined and using the blood of the murdered family as a catalyst. While forgotten by their descendants, their blood still carries their lineage's "strange power." Uryuu's own Magic Circuits had remained sleeping until that day, which unleash within him like a tidal wave in order to call out to Caster. While he used an unskilled summoning circle and he didn't perform the necessary chant, such things are only normally done as a precaution by magi to create a bond with a perfect, reliable Servant. If a human has a proper catalyst in order to summon a Servant, the requirements of the Grail can be met even if quality of the ritual isn't great.
He is shown to use a bracelet created from Caster's magecraft that allows him to easily enchant children into obeying his commands. Simply touching a victim places them into a trance where they will freely follow him to his hideout. The victims will remain in that state unless the bracelet is destroyed, which immediately frees them from the trance. Rin Tohsaka is able to use her own prana to counteract its effects and overload it much like her own jewel magecraft.