Berserker

Berserker is the Servant of Illya, who appears as a swarthy giant with adamantine skin and gross brawn. Though it is said berserkers are difficult to control and can turn on their Masters. However, Illya appears to have little trouble managing him. He was Hercules in his past life. During his final battle, Archer is only able to knock down some of his lives, and Rin able to only knock down one. However, Shirō and Saber perform a joint special attack with a traced Caliburn, Saber's lost Noble Phantasm, and eliminate the rest of his lives in one stab.

Personality
As a Berserker, he is stripped of his sanity and reason, acting feral and animalistic in combat.

Magical Skills
Berserkers are praised as members of the "Strongest" class. Berserker's main Noble Phantasm is God Hand: Twelve Labours, which grants automatic resurrection, up to 11 resurrections - meaning Berserker needs to be killed 12 times to be eliminated, one for each of Hercules's twelve labors. A secondary effect of his Noble Phantasm is that any attack of 'B' rank or below cannot cause any harm to him. Berserker also possess a Noble Phantasm called Nine Lives: The Shooting Hundred Heads, which is the legendary bow and arrow set used by Hercules to slay the nine-headed Hydra. This bow technique consists of nine consecutive shots, but can also be adapted for use on other weapons. Due to his class, however, Berserker lacks the necessary complex motor skills to successfully manipulate Nine Lives during the fifth Holy Grail War.

Weaponry
He wields a colossal axe-club, and is capable of causing massive destruction with the mere backlash of his swings. Shirō projects Berserker's own axe-sword against Dark Berserker to remove all his remaining lives in one go in a modified technique known as Nine Lives Blade Works: The Shooting Hundred Heads.