Choi Seungcheol is the prince of the Black Castle and Town. The Choi family is very harsh and hectic, they always punish the villagers even if they make such a SMALL mistake. Villagers are scared of them but they can't do anything but to obey them.

On the other hand/side...

Yoon Jeonghan is the prince of the White Castle and Town. The Yoon family is very nice and soft hearted, they help the villagers and make sure they're safe. Because of their golden heart, there are no crimes that was in their village and people in town get along really well.

However, they're not enemies. The Choi and Yoon family might look like they're enemies but they are actually very close.