Y'know something that could be fun~ This isn't Loui's first rodeo! He's possessed people before, the face Owen met? Not Louis' first/birth face. Just the suicidal daughter of a lord that was in love with a maid that got executed. Of course our Good Man Ghost will help her! He needs a body to help people with and she wants to leave the world for her lover, win-win right? And Even before that is was someone else.
We can even tie in Scott here if we wanted to. Scott has met Louis before, maybe on good terms, possibly on Bad! But Scott KNOWS that body jumper, maybe Louis is his Sudo-step Sire? (His actual Sire was just a random guy in an ally way(cannon)) Maybe Louis has tried/has possessed Scott in the past? Whichever way, Scott knows this man, and knows that he is like him in action but not intention. Idk if that's better or worse for Scott tho...
Somehow turn it into Bloodlothing??? Scott knows Louis is a Bad thing and so joins the Power of Friendship team in an "enemy of my enemy is my friend" way??
