Penance

He knew Yurika's answer to a proposal would be a clean slice to his neck, which is why he never planned to formally propose to her. Leo would have no choice but to subdue the princess during battle and chain her to the underground dungeon of the castle where he would breed her womb. Through a child born of mixed blood, the pair would become bonded for life.

But, Yurika's little sister was the only princess he could find.