i cant remember this for the life of me but it was a transmigration bl and one arc was abt an emperor ml and mc being 1 of 2 male consorts. he interacts w/ the prince a bit in the first few chapters and eventually gets him in trouble after revealing that the prince wanted to have drug him and a guard to defame him. ml tortured him to death accidentally bc he believed that mc was plotting to kill him after a maid gave him a half finished note i believe? and kept his corpse with him before eventually killing him self on top of mc's corpse by piercing their hands or wrists together.
It's in Webnovel titled, The Last X by 1381 Arc 3 EDIT: I just read the whole thing and it was what I just sent
shoot, was just reading the plot and remembering that story made me tear up. almost cursed the ML to die by thousand cuts. TT_TT
If I'm not mistaken, it was the only BE arc in the story but then again, that story was dropped in the end, so not sure if the whole story was supposed to be HE or not. Still, The Last X is still one of the best QT novel in my opinion, even if incomplete. You should try reading it.