Caster (Fate/Extella)

Caster (キャスター) is a Masterless Caster-class Servant granted control over the security of Seraph in the Moon Cell Holy Grail War. He is an independent Servant in the conflict of Fate/Extella.

Identity
Caster's True Name is, a "celebrated genius in human history"

Abilities
Caster cannot participate in the Holy Grail WaR due to his position as head of security, but he can still fight even if he cannot compete for the Holy Grail.