Villains who are either not evil in their original source material or are more vile than what they are in their original versions.
A prominent example of this is Max Baer, who was a Jewish boxer who accidentally killed a man in the ring. He was later made into the main antagonist of Cinderella Man, as a sadistic, brutal and misogynistic bully who bragged about the man he killed and wanted to do it again. This change caused quite a stir and Baer's family has spoken out against this, claiming that he had nightmares from that fight.
Sometimes, they do not redeem themselves in the adaptation, with Kurse, Sentinel Prime, King Stefan, and Bolivar Trask being examples; while sometimes they may redeem themselves to get close to what they are in the source material, Darkrai and Hades being good examples. Also note that not only does this apply to fiction; it can also apply to myths and legends like most versions of Hades who have been depicted as more eviler than his original version.
Note: Do not include people or beings from Abrahamic religion for this wiki is neutral on that sort of faith and that some may have disagreements about such. Also do not include real life people for they are only included in Fictionalized versions of true events, unless the real life person is a villainous parody of an original adaptation (i.e. Hermann Fegelein (Downfall Parodies) & Queen Victoria (Black Butler)) for instance.