Sion is the crown prince of the Kingdom of Sunkland. In the original timeline, he was one of the supporters of the revolution army, and was one of the people that wished for Mia's execution. He later becomes known as the Penal King.

In the current timeline, he is a person that Mia wishes to avoid at all costs so as to prevent herself from getting on his bad side and hopefully avoid her execution. This doesn't go as planned, and he ultimately has become one of her close friends. Mia also becomes someone he strives to be like.