Some time later, Culhwch had been arranged to marry his own stepsister, but he refused. Angry, his stepomother cursed him to marry no one but Olwen. Olwen's father, Ysbaddaden, was a vicious monster that would die if he was separated from his daughter. After many trials and tribulations, Culwch succeeded with the aid of Mabon and gained Ysbaddaden's powers and life.