Hi Pookie Bear, hopefully you haven't read any of these or at least some of these lol.
1. Corrosive - https://www.mangago.zone/read-manga/corrosive/
2. OΣG!!! = Oh My God = - https://www.mangago.zone/read-manga/o_g_oh_my_god/
3. Dreadful Night - https://www.mangago.zone/read-manga/dreadful_night/
4. Believe My Sign - https://www.mangago.zone/read-manga/believe_my_sign/
5. Dead Man Switch - https://www.mangago.zone/read-manga/dead_man_switch/
6. Ghost Gate - https://www.mangago.zone/read-manga/ghost_gate/
7. Murderer Llewellyn's enchanting dinner invitation (not really horror but rlly is obsessive and my personal fave tbh. Read it and you'll find out why I love the seme lolol) - https://www.mangago.zone/read-manga/murderer_llewellyn_s_enchanting_dinner_invitation/
As of now, these are the only ones I have read so far. My laptop is dying so I can't continue on digging my 'Already Read' list. Please let me know if you have read these or one of these. I would pretty much appreciate it if you'll share your thoughts after reading.
I'd say these are more thriller/drama since I (personally) don't think there's a huge market of good BL horror (also only some of them hot, others are just good reading). Unsettling themes nonetheless:
https://www.mangago.zone/read-manga/red_mansion/
https://www.mangago.zone/read-manga/salvation_spirit/
https://www.mangago.zone/read-manga/jikan_akima_jinbutsu/ (not possessive or hot, but horror and seems I rated it well in the past - I don't remember the story though)
https://www.mangago.zone/read-manga/black_mirror/
https://www.mangago.zone/read-manga/kansai_jin_to_hukuman_satsujinki/
https://www.mangago.zone/read-manga/obey_me/ (this one was RIDICULOUSLY silly, felt like a really odd KS wannabe at the time, you'll at least have a laugh)
https://www.mangago.zone/read-manga/madk/ (absolutely loved this one, ML isn't typical possessive, very aloof and not caring on the surface, we know what's up)
https://www.mangago.zone/read-manga/dead_man_switch/
https://www.mangago.zone/read-manga/ghost_gate/
https://www.mangago.zone/read-manga/sleeping_dead/ (another aloof ML, if you can call him that. Very different from the others above)
https://www.mangago.zone/read-manga/koisuru_psycho_no_shirayuki_kun/ (haven't read this one yet, but looks good)
I had to stop reading Red Mansion cuz it fucked my brain so bad lmao
So worth it thoughhhhhh
y'all I want some horror bl with a possessive obsessive hot seme please give good recommendations