Lambdadelta from Umineko: When They Cry
This witch has the mind-bending power to grant absolute certainty to events of her choosing. She can declare that candy will stay sweet forever or that someone will definitely die, and reality bends to make it happen. The subtle nature of her ability makes it even more disturbing than flashier powers. She doesn’t need to throw fireballs when she can simply make it certain that you’ll never escape her clutches, creating a feeling of inevitable doom for her opponents.