Boma

Mercenary.
A mysterious and silent refugee searching for his missing sister, Usagi, also known as Bunny. As punishment for a past crime, he was transformed into a "beast-human" hybrid; criminals who have committed offenses grave enough to warrant life imprisonment have beast heads grafted onto their bodies to make them regret their sins for the rest of their lives. Boma conceals his wolf-like features using a holographic device. He accepts a single job from Clair Leonelli—to destroy J—but ultimately refuses the assignment. He is a skilled swordsman and becomes a deadly enemy (and later, a powerful ally) to Daisuke and J.