Complete Monster/Mai-Otome

Anime

 * Tomoe Marguerite started out as a manipulative bully and Alpha Bitch who was in love with Shizuru, but after joining the Schwarz, she refused a Last Second Chance to rejoin the Alliance and threatened to kill them all because she enjoyed making people suffer and the lives of everyone but Shizuru was meaningless to her. She later says she does so because she "always get[s] what [she] want[s]", pretty much cementing her "heartless bastard" status in the eyes of a lot of fans. Her Karma Houdini status doesn't help.
 * Her "Monster" status is cemented earlier than that, when it's learned that.
 * Nagi, the Big Bad of the setting, is a dictator who takes over Windbloom, releases forbidden technology, and starts a world war, supposedly to encourage evolution, but in the end, he reveals he just wanted to see if humanity would kill itself if given the chance. He is taken lightly at times, especially before he puts his plans fully into action, but it is clear that he has no morals and everyone obeys him out of fear.

Manga

 * In the manga, Tomoe is Demoted to Extra and displays none of the repulsiveness of her anime counterpart. Her Complete Monster credentials are passed over to Big Bad, who believes that the world is full of lies and needs to be destroyed for things to be put right once again. Not only is he abusive and cruel towards protagonist "Manshiro", and not only does he manipulate most of the cast, but he also frees  in order to achieve control over   and , using them as weapons to achieve his ambitions. Then, with  under his control,  He is only stopped by  A pretty bad SOB, to be the counterpart of an overall decent person, huh?