Responses
Kataomoi Opera?
Is it by Harada? I read something that almost fits your description.. but there was no sister. It probably isn't this though.
http://www.mangago.me/read-manga/suimenka/
Yesss! It's Katakoi Opera! Turns out i had it but it was buried beneath so much mangas. Thank you so much! You guys are awesome. It wasn't Suimenka by Harada but i really loved that manga and the themes are pretty close, so thanks anyway <3
Looking for a yaoi manga i read years ago about childhood friends, the MC liked a guy in his class but the other friend sabotages his relationships or something and would get off from the comforting him after he was hurt. Oh the yandere friend had a sister who was equally messed up and helped him in his schemes XD Please help me out ive been searching like crazy