Amaterasu: Fire Fist

Amaterasu: Fire Fist is a technique using shape transform to the black flames of Amaterasu. The user is able to wrap his hands/fists into the black flames, and and use it as a unarmed weapon. Those inflicted, will have the flames on them until they are burn to nothing. The downside is the user, while slightly "immune" will constantly take damage on their hands if used for too long.