This entire series so far is in opinion... a haunting masterpiece. This series pushes all of the right emotional buttons, and in unexpected ways. The artwork is OUTSTANDING in every way, it takes lots of influence from Victorian era realist artwork. It also pays homage to Victorian Gothic literature, in it's story, tone and pacing.
The story is the highest point of this manhwa. The story starts of as a conventional fairy tale, but this is turned on it's head by having characters you ACTUALLY care about. The pacing and tone start out slow and light hear-ted, but it quickly picks up speed and becomes drastically darker and scarier in tone.

So I give this series a solid 10/10.