Sunghoon as a vampire prince Park Sunghoon is the son of the King of Vampires, which makes him a prince. When a vampire turns 18, they get their bat form, making them able to turn into a bat. In the royal family, it means also that Sunghoon has to marry. Of course the logical way is to marry the princess of the Moon Kingdom, combine the two kingdoms and make them even greater, and that's what Sunghoon's and the princesses family wants... but Sunghoon doesn't. He's fallen in love with someone else