Read this when I was young but never finished the last season, now I came back and finally finished it, and I have to say, this is really good. I understand the ppl who simply hate both main characters, bc of, well, OBVIOUS REASONS, but I personally couldn't avoid becoming emotionally attached to them. Maybe like a mother discovering that her child is a murderer/rapist, I felt sad reading their end even though I knew it was not only well deserved but also the only ending that I'd be able to accept really. After all Sangwoo did, his death was the only result that could have satisfied me, and the painful yet mundane way it happened was the only semblance of justice that could have been given to the victims, he didn't deserve to die peacefully, but he didn't deserve a great death to be remembered either. If I could change anything I think I'd have liked Bum to have been able to give the rings to Sangwoo, but then again, that would have only served to smooth a little my butter heart since he didn't deserve that kind of resolution either.
To the ppl saying Mei is infertile: He isn't, or at least it wasn't confirmed. When he was hospitalized the doctors told Masatsugu that infertility could be one of the consequences of misusing the suppressants but they never said he was at that stage (imo I think it's implied that it could have happened if he kept taking too many meds, not that he's already infertile)