Kenji Asai

The brother of a low-level yakuza boss, Kenji is extremely skilled at hand-to-hand combat and is even able to go hand-to-hand with the Aeons.

While he initially appears to be a sociopath, killing both soldiers and non-combatants without any signs of remorse, flashbacks show him to be a psychologically complex character who is driven by basic human needs such as love and meaning.