I don't know why but I get the feeling that Enshi(sorry if I spelled wrong)was the one who...

Me too! It'll be a huge twist if Enishi was the one who killed the cat because Kuruto was paying too much attention to it.

i don't think so... Yukito should be the one who killed the cat...

I don't think either of them killed the cat. The blood probably came from elsewhere. It doesn't seem like that kind of manga

Enishi wasn't there when Kuruto first got the cat. In the manga it said that Enishi came to live with them after Yukito left. When it showed Enishi and Kuruto looking for it, it was after Yukito supposedly killed it.