Can I get a dark and edgy relationship? And when I mean dark and edgy I don't mean rape,...

Olgami
Merry psycho
Flowers are bait
For your murder
hotaru no yomeiri
Dead Flowers (Dami & Zetson)

peak https://www.mangago.zone/read-manga/black_mirror/

https://www.mangago.zone/read-manga/free_in_dreams/
https://www.mangago.zone/read-manga/red_mansion/

this ones so good