So here's another fun idea I'd like to try!
Grim is a Guardian (kinda like an angel but they're made from the ash and blood of a phoenix) he got corrupted sometime during the Great Demon War. He was once a warrior for the Gods and protector of the mortal world, but now he's over thrown the king of the largest kingdom in Telvarra (their world) and he is amassing a great army of dark warriors in the hopes of taking over the world. By his side, his daughter Jynx. She was very young during the war and the time of her Father's corruption, so she only ever knew him to be a cold and violent man, and had been raised to be that way herself. However she isn't as cold as her father, and she's not really evil at heart. This is thanks to her mother who her father keeps locked away in a tower because otherwise she would interfere in his plans, but some part of him still loves her so he doesn't want to kill her.
Now this is where the story can go a few different ways, her mother could convince her to leave, to be free and live her own life. If she does chances are she's going to somehow run into YC, probably in a nearby city or maybe a village outside the kingdom. Her father sends guards, bounty hunters, mercenaries or something of that nature to retrieve her. She sees what he's doing to the people, the kingdom, the land etc. And decides she has to stop him, with your help of course.
Or she could meet YC while in her father's kingdom, you'd probably be a slave or something that works in the castle, they become friends and Jynx helps them escape. Once again he sends people to find her and she sees what he's doing and decides to stop him.
Or her father sends her out on some mission, to kill someone whose interfering in his plans, probably YC, they meet, but she doesn't want to stop them, she wants to help him because she thinks her Father's gone mad (which he has.)
So if you want to take on this idea with me, I can give you a more detailed back story upon request. So PM me if you're interested.