I want to write a villian that didn't know he became a villain until a rebellion and make him sympathetic but not to the point of being a woobie and forgiving him of his actions. Any tips?
How do you write a villain?
Flesh him out into a three-dimensional character, and make his core motivations for his villainy sympathetic-but also make it clear that his motivations don't excuse what he's doing in the present.
Villians think they are the hero, they think the actual hero is the villain, so write his motivations as being a hero blind to the destruction they leave behind
Just think of everything that can break a human being, do the worst and then have the protagonist be responsible for it.