Self-explanatory title, declare your contenders here for the most evil, malignant, maleficent, inauspicious, ignoble, nefarious, diabolical, atrocious, heinous, vicious, sinister, foul, vile, and unholy beings in all of fiction.
And by evil, I don’t just mean some plain evil monster or criminal, I mean the most, absolute evil thing in all of the infinite universes of fiction, of enormity and baseness objectively beyond all the wrongness capable by anything multiplied thousandfold.
Probably Black Zetsu, since his one sole purpose is to resurrect his mother, Kaguya Otsutsuki. Her resurrection would allow her to absorb all chakra (basically the Narutoverse equivalent of magic energy) on Earth back into herself. She would then make all living beings white zetsus, her slaves.
Black Zetsu is manipulative, and changed the course of history with just a silver tongue. He was able to twist a kind boy into a heartless man with intent on killing his brother just to take a position of power.
Based on the very limited amount of media I’ve consumed, the most evil characters I’ve seen in fiction are Arthur Mitchell from Dexter and that Eldian king from the Founding Titan flashback from AoT.
:sunglasses 
