Responses
http://www.mangago.me/read-manga/kobi_no_kyoujin/ İf you still didnt read it
Kawaii akuma is this way and the spin off about the middle brother has him be a stalker...but its played for laughs... scarlet....madarame hiro in general actually
http://www.mangago.me/read-manga/akuma_wa_hohoemu/ this one hes obsessively in love...and you see some of their story in the original series
http://www.mangago.me/home/mangalist/67144/?filter=&page=2
Gimme something with a really possessive lover or a yandere(ish) (≧∀≦)