It could be a “kin” thing, but the whole “this is what I really look like, not like this body” and the amount of “look at what I really look like” screams DID larp to me. It was popular among high school kids larping DID to make these edits of what the fictional character they’re larping really looks like versus how they see themselves, like changing the color scheme or hairstyle. Is this person they’re interacting with a teenager?
I don’t know much about kinning and I think they sometimes use the term source, but in recent years the fake DID craze co-opted it for when they pretend to have a multiple personality that’s a direct copy of a fictional character or real life person, and they point to the media they “formed” from as their source, other alters from that media their “source mates” and pretend to have pseudomemories of things like for example pouring acid into a kid’s brain, and calling them “source memories.” I’m sure My Friend Dahmer blurs the line for these people between fictional source and “hey I’m pretending to be a real person who tortured real people.”
It gets to the point where DID larpers don’t want to interact with other “alters” from the same source, that makes them uncomfortable or triggers their trauma in some inarticulable way. I guess there’s only so much attention to go around and it’s not fun anymore if everyone pretends to be Jeffrey dahmer.