Spartacus

Berserker of "Red" (“赤”のバーサーカー, "Aka" no Bāsākā) is the Berserker-class Servant of Deimlet Pentel of the Red Faction in the Great Holy Grail War of Fate/Apocrypha. Shirou Kotomine assumes command over him before he even meets his Master, but Berserker goes rogue before Shirou enacts his plan to officially become his Master.

He is instead forced to contract with Caster of Black when captured by the Black Faction.

Berserker's True Name is Spartacus (スパルタクス, Suparutakusu), the strongest Gladiator and the ringleader who raised a large-scale rebellion of slaves in Ancient Rome known as the War of Spartacus.