86 Votes in Poll
Robotnick
robotnik without hesitation, he gained so much power that he can match and surpass the big bang
Definitely Evil Morty, he killed several ricks throught the multiverse, he ran for President on the citadel and won, and then he destroyed the central finite curve as well as most of the citadel.
I want to say Yzma because Magic... but Robotnik has more impressive feats...
Edit: but then again, Evil Morty is an absolute monster...
@Meta-Magician
Yzma was more of an arcane chemist then an actual witch, an alchemist.
What do you think?