This being is known as Fused Zamasu, a creation of the potara earings. An Immortal god that cannot be defeated. His only desire is to enact the Zero Mortal plan. The Zero Mortal plan, is a plan that has been eluded to as mass genocide of all mortals and the gods that failed them. This was to be carried out in every universe until no one was left, and he was able to shape the earth as his utopia. Too bad that he has found you…