Jikan Akima Jinbutsu
Complete | RINNO Miki | 2000 released
There are 4 different stories but the same character (Not in the same timeline I believe, it's like a multiverse type thing), 1st and 2nd were my favorites.
Red Theatre
Complete | OGAWA Chise | 2000 released
Brutal: Satsujin Kansatsukan no Kokuhaku
Ongoing | Koga kei,Izawa ryo | 2019 released
Nishikaidan No Akuma