Berserker (Lü Bu Fèngxiān)

Berserker is the Berserker-class Servant of Rani VIII in Moon Cell Holy Grail War of Fate/Extra. He is only fought as an enemy Servant during Rin's route.
He was an infamously treacherous military commander Lü Bu Fèngxiān, and his name was made household in the Romance of the Three Kingdoms.