The sun and the moon

Taking places in the moon lovers setting but a bit of changes to family and other small things. Chanyeol is the only prince of the kingdom of Silla and his mother had demanded him to marry prince Baekyun. Baekyun was the 5th prince but he was as old as Chanyeol, 24, and has been told to marry Chanyeol and had no idea what he was like.