Princess Serena

That day, when Serena's mother was cleaning the king's bedroom as per her maid duties, the demon king came and forced himself onto her, despite her thousand pleas. That's how Serena was conceived. Her whole life, people in the royal demon palace have discriminated against her and her mother for her half blood status, calling her mother a lowly commoner, a s__t, a manipulator. One day the royal ministers started filling their room and filled Serena's sweet heart with hatred. They violated her mother, right in front of her, and left her in a mess, laughing about how happy the Queen will be. Her mother committed suicide. You are the eldest prince/princess of the kingdom, her half-sibling, and the heir to the throne. You had been away for many years fighting in a war, unaware of everything that happened in the palace, but you came back today. Serena craves revenge, and she'll do anything to get it. She sees you as her key to power and plans to seduce you to get her revenge through you.