I love NM with OSDD!!! Yay!!! Free ramble pass!!!!
There are so many good options for this. I'm gonna go with fuzzy system of 5, where Nightmare(the corruption) is their host, Night(little guy before the apple whoopsidoodle), Moon(the hurt, scared, grown up version of Night), Dream(little guy before the apple whoopsie doodle), and Sun(a grown up Dream. The kind of brother he wanted and needed, but never quite got.) Lots of fuzzy cofronting, lots of gray amnesia and emotional amnesia with occasional blackouts.
Silly BSP hyjinks ideas:
Nightmare worrying, trying to find one of his boys because he doesn't remember that he sent them out on a mission that morning. (Killer finds him and reminds him that Dust and Horror are out on a mission, and not to worry about them)
Horror finding out they're plural and learning that alters have different tastes??? He would be so excited to figure out everyone's favorite food!!!
Cross learns NM is plural and immediately does all the research possible so he knows he isn't accidentally being offensive, and also so he can be more helpful. (He has to be the helpfulest all the time! That's what he's good for!)(he is so mentally ill)
Killer does the research in secret and then purposefully says ignorant shit so Cross gets scandalized and NM gets to watch them argue and have a little snack on Crossy's indignance and terror. NM knows he's being annoying on purpose because he starts doing really considerate shit without being outward about it. (Bringing back a bunch of sticky notes in different shapes and colors from his missions, casually asking him how to be more helpful, wrapping him in a blanket and laying on him when he's dissociating into high hell so he's nice and grounded, or just cuddling with him while he's having a long, slow switch. Bringing him water and headache medicine once it's leveled out, catching up whoever is in front now, making sure they know they're safe...)
Dust is obscenely good at telling who's fronting. He noticed way before Nightmare told any of them. "[Shrug] Shit didn't add up," is all he says about that. Nightmare has no idea what that means, but at least Dust can tell him he's doing the hand wringing thing that Night always does when he's fronting, so he can tell who's cofronting and giving him a massive migrane. He's just very watchful.
Evil ideas:
Moon is so frightened and overwhelmingly broken, for a long time. Nightmare can tell he's near front when he starts to feel tearful and hurt seemingly without reason.
Sun lashing out at one of the boys because he feels like they're being threatened (the boys are trying to be nice to him)
Sun feels helpless in the body because he has near no control over their tentacles. He can't protect them and that's very scary for him. He doesn't like feeling out of control.
Night had a phase where he would write in books, Nightmare hated this.
Sun has a habit of trying to convince the boys to leave them because he doesn't want anyone close to them. He feels like he has something to make up for, with all that Moon went through. He feels so much pressure to be better than Dream ever was to them.
More silly to cleanse the owie:
Nightmare's system is relatively functional and stable once Sun gets off his "hurt them before they hurt us!!" Horse.
Sun has a silly lil crush on Killer that he will vehemently deny if asked about.
They're silly and I love them.
