Uryuu Ryuunosuke

Ryuunosuke is a young man with a slender build, messy bright orange hair, and wide, expressive reddish-brown eyes. He typically wears a casual orange and brown jacket over a white shirt and dark trousers. His youthful and energetic appearance masks a deep, unsettling madness reflected in his frequent manic grins.

Psychopathic, eccentric, cheerful, nihilistic, artistic, and inquisitive.

Serial Killer and Master

A prolific serial killer who happens upon an ancient book of occult rituals in his family's storehouse and accidentally summons the Servant Caster during the Fourth Holy Grail War. Lacking traditional magical knowledge, he forms a deep bond with Caster based on their shared philosophy that murder is a form of art. Together, they terrorize Fuyuki City by conducting gruesome experiments and kidnappings to explore the nature of God and human suffering.