i started reading this manhwa today and i finished it in 2 hours. it was very very interesting and full of surprising moments, i loved the development of characters especially the sister, the brother turned at the end to be the psycho one not his sister. gi-hoon was really an interesting character too, i thought for once that it will be a boring love triangle, hopefully it wasn't. the events were unexpected and the ending was satisfying to me, i can't think of better ending even it was really sad and made me feel depressed (damn i hate this feeling)
i'll give it 10/10 especially especially that i love siblings incest.