I really don't know, he's hard to read, because it seems like he is really dumb, but then you wonder if he really is that dumb, he has been doing lots of things we actually don't know about yet. And I think he probably knows about what happened to Jingi, but he has no idea of what Jingi is plotting. I think this story has a long way to go.
I really want to see his reaction to the tatoo! I'm sure he will be furious and surely we need more information about him.
Another thing that worries me is how Myeongil siblings would end up involved in all this since they are classmates with the uncle's daughter and I am sure that it will have some impact in the future, I don't imagine the author making them classmates as a coincidence only.

I expect Heonjae to show his true colors, I think that Myeongil still hasn't seen what Heonjae is capable of. On the other hand, Jingi has shown all of it, the bad and the good parts.
I don't expect a happy ending of this story, but if Myeongil has to end up with someone I'd prefer Jingi.