Because of the magic a Warlock must learn, it puts tremendous pressure and stress on the mind. This often corrupts said mind and leads it down a path that cannot be returned from.

Tenshi’s, however is different. He managed to extract the pure essence of his hatred and anger into a being, a counterpart if you will. Akuma is controlled by Tenshi (in his power), and has he same traits. He’s a bit violent, uproarious, and bad mannered but holds the power of thousands of ancestors in his veins.

Tenshi, if all else fails, can merge with Akuma to create a unified being of destruction. He doesn’t yet know how to control his form, so he refuses to use it in the presence of Mysticus.