Goku Black / Zamasu

Goku Black is the mortal identity of Zamasu, a Supreme Kai apprentice from Universe 10 who became disillusioned with mortals and sought to exterminate all mortal life. Using the Super Dragon Balls, Zamasu wished to swap bodies with Goku, gaining his immense Saiyan power while retaining his divine ki and techniques. As Goku Black, he terrorized Future Trunks' timeline, killing countless mortals in his 'Zero Mortals Plan.' His fusion with his alternate timeline self, Future Zamasu, created Fused Zamasu — an overwhelmingly powerful being that threatened the entire multiverse until Zeno was summoned to erase the timeline.