This author NEVER fails to make me breathless, and is the first to own 2 spots in my top favorites. When I have money, I'm immediately buying these in paperback.
Here's the link to one, but there are multiple, also they are all in korean https://miyobooks.com/products/wolf-in-the-house-5
This was really intense, and the only manwha that has creeped me out this much. I think the plot was really good and could've been more strong if only the author had added what happened after they stepped through the mirror, and how everything would look in the human world from now on. Definitely Understood the author wanted a more ambiguous ending, but still wish there was a bit more before leaving it off.