I think that later I will make them as experiments for my work-in-progress hack of Knave/5e/AD&D/any-other-things-that-have-rules-I-like-and-want-to-steal.
The first and better idea is for a probably evil wizard who uses illusions, invisibility, stealth and especially the phantasmal spells to terrorize and torment his enemies, in the style of 70s/80s horror movies. More specifically I was thinking of Suspiria, but even Hereditary could be a good reference for this kind of use of magic. Hell, even Halloween has that bit where Michael sets up all the corpses in a very theatrical way. I bet Michael would've been a theater kid if he had made it to high school.
A buddy of mine brought up Hausu as well, which I have not seen in it's entirety, but which seems very relevant to this idea.
The other idea was more of a straight-forward adventurer/hero type. Probably a fighter, maybe even a paladin. This would be a slightly different way to play a chaotic neutral character who has a save-the-world type quest.
The scene I initially imagined was one in which the party was in a settlement buying supplies for their next expedition into the mega-dungeon or whatever, during which time this self-righteous fighter would be robbing the innocent potion-maker at swordpoint and justifying it by being like "we need all the help we can get, you'll thank me when we save the world". It's murder-hoboing for a cause. Maybe with less murder.