Replying coz I also wanna know
I’m not 100% sure if this is right (I’m not that far in this story) but could it be ‘See You, My King’ ?
- https://www.mangago.zone/read-manga/see_you_my_king/
ive read this one!! unfortunately its not both the MC & ML wore red iirc
i did a bit of searching through my tags, its this one
https://www.mangago.zone/read-manga/martial_brother_please_don_t_run_away/
The og has 92 chp, so its currently 12 behind from completion
hello! im lf a bl manhua, the mc and ml are cultivists but so much time passed that the comic is set in the modern day. the ml is a cultivist who brought back his dead lover (MC), and they live underground in a large tomb(?). the manhua starts with MC waking up in a giant coffin surrounded by nature, theres some servants who help ML guard the location. People also try to raid it for the treasure inside. iirc theres this arc later where its revealed mc is actually some kind of regressor who possessed a body to stray the ml away from villainy??? something like that. The MC also needs ML's blood to live bc he's basically a zombie/ghost