I wanted to say this before, but I wasn't in the mood to type. People who compare this manhwa to The Beast Must Die seem to not understand that they belong to different genres. You obviously won't get the same "thrill" as The Beast Must Die when you read this one.
Here I really like the complexity of their characters and how their codependent relationship is shown. Plus when they're so fucked up their character development becomes more delicious. I hope there will be some though.