I liked the first episode, but I fell completely in love somewhere around 4th or 5th episode. I love the wordbuilding and I love all the main characters. And a few times each episode I just had to say aloud "God, he's so beautiful" about Song Joong Ki, because he really is so beautiful here. :)

I admit that it was a bit too brutal for me sometimes and I had to fast-forward through a few scenes. But it isn't relentlessly dark. I finished it yesterday and I want the 2nd season now, now, now. Unfortunately I will have to wait a while. :)