And some of you will probably hate him even after he has his redeeming moment, but it's a staple of Korean dramas for all of the main cast to never be bad guys. The villains always disappear or become "good guys after all."
My prime example: Winter Sonata.
Sanghyeok was supposed to marry Yujin. Chaerin was Minhyeong's boyfriend.
But because Minhyeong turned out to be Junsang (amnesia, they all thought he died when they were in high school), eventually both Sanghyeok and Chaerin redeemed themselves.