TV-Series
Description
Kirei Kotomine is a central figure in the Fate/stay night narrative, serving as a priest at the church in Fuyuki City and the official supervisor of the Fifth Holy Grail War. His role, however, is marked by profound duplicity, as he is also a clandestine participant and the war's most significant saboteur. Kotomine is a man of deep contradiction: a former member of the Churchs Eighth Sacrament, a agency responsible for the management and recovery of holy relics, he was also an Executor, an agent trained to hunt down heretics. Through an agreement between the Church and the Mages Association, two organizations normally hostile to one another, he was seconded to the world of magecraft. He studied under Tokiomi Tohsaka and, as a result, became the legal guardian of Tokiomis daughter, Rin, following his masters death.

Standing at 193 centimeters with a lean, athletic build, Kotomine cuts an imposing figure. He typically wears a dark purple, high-collared coat over his priests vestments. His brown hair is kept slightly long, and his expression is often described as serene yet carrying a profound emptiness, a blankness that hints at the turmoil within. Physically, he is exceptionally powerful, having mastered the Chinese martial art of Bajiquan, a style he has warped into a brutal form of human destruction. He is also a highly skilled close-quarters combatant and an expert in the use of Black Keys, which are throwing weapons used by the Church. While the hilts are physical, the blades themselves are manifested from magical energy, allowing him to carry dozens at a time. In addition to his martial prowess, his faith, though twisted, is genuine, granting him the use of the Baptism Rite, a powerful sacramental chant that is exceptionally effective against spiritual entities. This proficiency against wraiths and Servants is a hallmark of his combat style.

The central conflict defining Kirei Kotomine is his inability to experience pleasure from things that normal people consider beautiful or good. Since childhood, he has been plagued by a fundamental defect in his nature, finding enjoyment only in suffering, despair, and the misfortune of others. He is a man who thoroughly understands the difference between good and evil, yet can only derive satisfaction from sin. This awareness of his own twisted nature drove him to desperately seek a cure. He entered the priesthood and threw himself into martial and spiritual training as a form of penance and self-discipline. He even married a woman named Claudia, hoping that the love of a family would make him whole. This effort ended in tragedy when his wife, realizing the depth of his hollowness and despair, took her own life in an attempt to make him feel something. Instead of grief, Kotomine felt a profound, disgusted disappointment that he had not been the one to kill her. This event broke him, leading him to abandon all hope of salvation and embrace his innate nature.

His purpose in the Holy Grail War is not the ancient artifact itself, but the process and its ultimate result. He became fixated on the fact that the Holy Grail was corrupted by a being called Angra Mainyu, a manifestation of All the Worlds Evils. To Kotomine, this tainted, malevolent curse was a mirror image of his own soul. His driving motivation is to see this evil born into the world, to witness the destruction it would cause. He believes that by observing the nature of this pure, untainted evil, he might finally understand the reason for his own existence and find an answer to the question of how someone like him could be born. For him, the suffering of others is not a means to an end, but the end itself a state of being he refers to as "pleasure."

Throughout the Fifth Holy Grail War, Kotomine manipulates events from the shadows. In his capacity as supervisor, his duty is to protect the secrecy of the war and grant sanctuary to Masters who have lost their Servants. In practice, he is a direct participant. He is the Master of the Servant Lancer, having cruelly ambushed and dismembered the original Master, Bazett Fraga McRemitz, to steal her Command Spells. He is also the partner and de facto Master of the Servant Archer, Gilgamesh, a relationship forged during the previous war after Kotomine betrayed and murdered his own teacher, Tokiomi. His relationship with Gilgamesh is unique; the king of heroes is neither a tool nor a subject, but a collaborator who encourages Kotomines hedonistic pursuit of suffering.

His relationships with other characters are defined by his nature. He is the primary antagonist to the protagonist, Shirou Emiya. The two are presented as foils or mirrors of one another. While Shirou lives with a borrowed ideal of saving others, a path born from a traumatic fire, Kotomine is an "empty" person who finds his only meaning in destruction. The enmity between Kotomine and Shirous adoptive father, Kiritsugu Emiya, was the core of the Fourth Holy Grail War. Kiritsugu, a man who sought to save the world by sacrificing the few for the many, was the only person Kotomine could truly hate, and he found immense fascination in trying to understand him. This legacy of hatred and incomprehension is passed directly to Shirou. With his ward, Rin Tohsaka, Kotomine plays a more sardonic role. He is her teacher and guardian, but she despises him, correctly intuiting his malice. He is not a kind protector; his care for her is negligent, and he famously mismanages her familys wealth into near-ruin.

Kotomines development across the routes of Fate/stay night shows his singular will. He is killed by Shirou using a ceremonial dagger gifted by Rin in the Fate route. In Unlimited Blade Works, he is killed by his own Servant, Lancer, for his treachery. It is only in the final route, Heaven's Feel, that his character arc fully culminates. Here, his failing body, kept alive only by a corrupted, artificial heart granted by the Grails mud, finally gives out. He engages in a brutal, final fistfight with Shirou as the Grail is about to be born. In his last moments, dying of a broken body while his opponent still stands, he acknowledges Shirou as the victor. His story concludes not with a dramatic defeat, but with the quiet expiration of a man who finally, in witnessing the lengths to which his enemy would go, ceased to question the meaning of his own existence. His legacy is that of a "villain" who is not driven by greed or power, but by a philosophical sickness, making him one of the most uniquely disturbing and compelling antagonists in the medium.