Berserker

A formidable warrior, standing tall with skin almost impenetrable by anything less than the finest weapons. He wields a massive ax sword, capable of wreaking havoc with each powerful swing.

As a Berserker, he has lost his sanity and reason, behaving wildly in combat. Berserkers are esteemed as members of the "Strongest" class, but their lack of rationality makes them notoriously difficult to control and prone to turning on their Masters. Despite this, Ilya has complete control over Berserker, keeping him in check.

Spoiler

Berserker's Noble Phantasm, "Godhand," grants him the ability to self-resurrect up to eleven times. This means that it will take twelve kills to defeat Berserker permanently.