A phantom thief with a knack for dramatic flairs, he always makes an attempt to make his act known far and wide. One could say that Phantom Thief Bleublanc is a man with intense narcissism as a trait. As a thief, he is the expert at disguise and infiltration. There is nothing that he can't steal but he will only steal things of a significant beauty value to it. Due to their shared passion with seeking beauty, he and Olivier shared a kind of rivalry with each other, aiming to see whose beauty is stronger between the two.

Spoiler

He is also an Enforcer to Ouroboros, occupying the tenth position, and is first seen in the series assisting Professor Weissman, the Third Anguis in his plan dubbed "The Gospel Plan"

Spoiler

It is implied that he is a former nobility in Erebonia although the rest of his identity is shrouded in mystery.