sasaki kojirou (fate)
Fate series character. An Assassin-class Servant who appears in Fate/stay night and Fate/Grand Order.
He has blue eyes and blue hair tied into a ponytail. He is often seen wearing Japanese clothes and wielding a sword.
In Fate/stay night, he is a Servant summoned by Medea (caster), another Servant, which is normally against the rules of the Holy Grail War. This makes him weaker than a normal Servant and dependent on Caster for mana. In the Heaven's Feel route, he is killed and his body is used to summon Hassan of the Cursed Arm, the True Assassin.
True Name: Sasaki Kojirou