9. Eveline (Resident Evil 7)
The story of Eveline is a decidedly morally complicated one.
On one hand, Eveline is basically just a child with monumental powers who wants to be loved and cared for.
Created as a bioweapon who could infect people with Mold in order to control them, she was naturally regarded with a lot of fear by those charged with watching her. Eveline doesn't really appear to have been taught manners or even to not murder people in order to get what she wants.
But this childish streak would quickly become a sadistic one, as the bioweapon baby would escape and then infect the family who took her in, using her powers to warp them all into terrifying monsters who were unable to free themselves from her control. This is exactly what makes the character so terrifying, as she is simultaneously a sympathetic character, and an awfully cruel tyrant.
Also she becomes a terrifying ooze monster at the end, which lands her pretty solidly in the 'spooky bad guy' category.