Responses
Ff
not really yandere x yandere but htis was the first one which popped up in my mind
http://www.mangago.me/read-manga/flaver/
or this http://www.mangago.me/read-manga/yoru_mo_hi_mo_akenai/
may this too? or more like yandere x violent tsundere?
http://www.mangago.me/read-manga/rakuen_no_ori/
FF
Umm... Any yaoi manga where Seme and uke are both yandere?