Not evilest (genocides, infanticide, and the like are no fun to read or to think about), but toughest, strongest, most dominant. How do you become the Doctor Doom Supreme of this universe?
You don’t have to explain how you accomplish your task, just what you would do.
Fun answers encouraged; don’t be a bummer. (marking NSFW just in case to make mod’s lives easier)
I genetically engineer puppies that explode on their third birthday, give them out for free to the heroes and then strike during their moment of grief for an easy victory.
Alternatively, I wait untiã someone else cotquers the Universe and then use the exploding puppy trick on them.