I only watched this dire historical drama years ago because of the two main male actors whom I had enjoyed in other works, namely Jo Dong Hyuk from Lover (2005) and Seo Do Young from Spring Waltz (2006). All I can say is both men must have been desperate for money to agree to work in this badly written, badly produced drama that leaves a bad taste in your mouth even long after you've concluded it.
I cannot recommend this drama at all for any reason. The story is hackneyed and stupid, and it even shocked me by having nudity in it. I was attracted to the K-drama genre in the first place because it was generally clean entertainment that I didn't have to worry about my kids inadvertently watching bad stuff as they walked through the den while Mom was watching something. This one I was glad I watched late at night, by myself when everyone was asleep, but honestly I even found myself fast forwarding through a lot of this Cain and Abel type story because it simply wasn't interesting. There were no characters to admire, which is a death blow to any K-drama. No one was redeemable either. This drama was a total waste of my time, so instead of going on and on about it I would simply tell you to avoid it at all costs. There are FAR better historical dramas out there. Trust me. I've watched 350 K-dramas. I know what's trash and what is mediocre and what is great. This is at the trash level. Avoid it like the plague.