Her Leopard Guardian

Crystal Winters saves demon lord Moro, resealing his power bell. Her greedy uncle and aunt force her to marry a villain; Moro protects the Winters family. When the villain steals the bell, Moro transforms into Crystal, enters Shaw family, and thwarts schemes. Crystal stops Moro from killing them; he punishes the villains. He sacrifices himself for Crystal's parents, winning approval. They overcome prejudice, transcending human/demon boundaries to be together.