The Beyonder
The Beyonder is villain in the same way that Galactus is – however, even if he isn’t set on ruling the multiverse, he still acts like a big baddie. How else could he be called when he kidnapped heroes and villains alike and sent them to Battleworld?
The Beyonder is, basically, the God of a multiverse and can be called the one responsible for the creation of the Molecule Man (after all, Owen Reece became a supervillain after he accidentally accessed the Beyonder’s dimension). The power of the Molecule Man was just a fraction of the Beyonder’s power – so what can we say about that?
He has, basically, every power known in the Marvel multiverse – multiplied by millions, of course. So feats like destroying galaxies were nothing to him – even the most powerful entities in the Marvel multiverse had no chance against him (even if Death, Eternity, and others are, essentially, unbeatable).
Some might even say that even a fight against The One above All would end up with a draw… So he is above anyone else you might think of.

