I'm a god. I will live forever.
~ Hades
I Zamasu, am the sun that shines on this world and what I radiant is divine justice. I am the knowledge of the universe. Begone where my light shines.
~ Fused Zamasu to his enemies.
Villains who are Deities (Gods) or have a level of power so great they are equal to such cosmic beings. Needless to say, these are some of the most powerful villains of all due to their nature.

To count as a deity, a character should also have been worshiped, either in the past or present; some deities may even require said worship to function. Sometimes, these beings rule the cosmos and do not want anybody to rule in their place.