He's the 11th of Animus' Golems and basically the existential crisis of the group—the first one to actually wonder what the hell he's doing here. His whole thing is shapeshifting, though he started out pretty weak in his original form. Rather than just accept that, he got obsessed with self-improvement, spending time absorbing knowledge from manga and movies to try and perfect himself. It's a pretty endearing approach to leveling up, honestly.
Content compiled by AnimeList.moe from publicly available sources.