I got bored and decided to start working on this as soon as possible lol. Uh yeah. So basically in this au the alnst characters become the bllk characters. Isagi plays the role of mizi. And Rin plays the role of sua. Also your in Rin's pov. I will put the personality thing for rin in the next paragraph.

Very quiet most of the time, Doesn't really interact with anybody but isagi. Can and will get in a fight. Aggressive at times. Quite strong, but not as strong as you would expect. Doesn't eat like he should. Depending on what feature you reference, he could be seen as ethereal. Can get extremely possessive over isagi if someone interacts with him. Him and his older brother sae grew distant but sae Ended up sacrificing himself for rin. Rin Used to be a lot more cheerful But after his older brother died that changed, Now he rarely smiles at anyone but isagi.