Wiseman/Death Phantom, the Big Bad and Eldritch Abomination of the R season of Sailor Moon, is definitely this. He corrupted and manipulated the rebellious Black Moon Clan of Nemesis into become villains and used them to turn the peaceful, utopian Earth of the future into a barren, desolate wasteland, Mind Raped a vulnerable little girl into becoming his servant and tried to have her kill her future parents and friends, turned one of his pawns into a monster and knowingly sent her to her death, sadistically blasted to death another minion in front of that minion's older brother for having outlived his usefulness and attempting to screw up his master plan, and planned on destroying the universe for the sheer hell of it.
And in the manga, Wiseman was a mass-murderer before being possessed/merging with Death Phantom. Oh, and guess who is shown being the one to start Galaxia on the path of being manipulated by Chaos in the final arc? Make no mistake, all (manga) or nearly all (anime) Big Bads in Sailor Moon are OmnicidalEldritch Abominations, but Wiseman just puts a personal touch on the whole business of causing The End of the World as We Know It.
He was a piece of work in the manga as well, sending the Four Sisters on much more destructive evil missions than they went on in the anime and taking sadistic pleasure in capturing the Sailor Senshi in front of Usagi's eyes. Unlike in the anime, the Four Sisters probably also qualify for Complete Monster status in the manga, especially Cooan, who burns an innocent girl to death with no remorse.
The manga version of Shuichi Tomoe was no slouch. He was supposedly a loving father once (or at least Hotaru thinks so), despite being a Mad Scientist even then. He completely snapped after the accident in his lab that crippled Hotaru (her manga self is a heavily scarred cyborg, thanks to it) and killed her mother, willingly joining Death Busters and implanting the egg of Mistress 9 into Hotaru's body without any sort of second thought. He also had a massive A God Am I complex and wished to create a new race of superbeings, starting with himself. Thank God he was much more toned down in the anime, where he was mostly a Brainwashed and Crazy father who made a Deal with the Devil to save Hotaru after the freak accident - not knowing that they'd be rendered insane in different ways.
