Responses
I'm reeaaally not sure, but is it this one?
https://www.mangago.zone/read-manga/the_uninvited_guest_on_my_shoulder/
no, sorry. it isn't that one ╥﹏╥ but ty
not sure on the species that the uke(?) was (maybe demon? an incubi? idk but it's something supernatural) but i remember a scene (either in an extra chapter or the end chapter) where he passes by a side character in the story, stares at him and goes "heh, you really ARE an old man now" bc that side character was the same species as him but turned human.
side character and top i think works at the same place (can't recall the job) and i dont recall how they look either T_T