"Overlord" can also mean lord over other lords and more, etc., etc., etc., like Bowser (even if not "pure" evil) for an example, he's pretty much an overlord throughout the Mario series, and is already confirmed to be one. Ozai, Fire Lord/Pheonix King, he's pretty much almost like an overlord (if not actually is) too, in different ways. There're lots of characters in movies/films tv shows (or "other 'different shows'" like " shows "plays and theaters/theatres for example(s)), anything character that is actually in overlord in books, shows movies/films, games, anything like that.
https://antagonists.fandom.com/wiki/Category:Overlords
https://www.reddit.com/r/HazbinHotel/comments/1aok9tv/whats_the_difference_with_overlords_deadly_sins/
Even "Dio Brando" is an "overlord," and so is "the High Evolutionary" too.
https://comicvine.gamespot.com/wundagore-ii/4020-57808/
https://pure-evil-villains.fandom.com/wiki/Category:Overlords
https://evil-overlords.fandom.com/wiki/Special:NewFiles