Stumbled on someone decrying TikTok "multiplicity kids" on twitter, but not sure how I feel about this thing and there's no wikipedia article which is usually the limit of my research.
On one hand DID and OSDD are real things, though some people say it's a culture specific disorder.
On the other kids having calling themselves "we", claiming to be piloted by Harry Potter characters, real-life serial killer and Minecraft YouTubers seems to silly to not be just good clean fun.
On the third hand is you told someone thirty years ago about gender spectrum, genderfluidity, xenogenders, bi lesbians, autism spectrum, they'll probably think you're insane. Maybe there is a subclinical version of DID, like Asperger's to autism, so to speak? I dunno...
Yeah, the whole headmates thing seems to be mostly kids on social media self-diagnosing themselves with "multiple personality" disorder of some sort and forming a culture with it's own therminology and a whole bunch with progressively more granular microlabels. I've seen kids do this with asexuality, but asexuality seems to be a not to uncommon phenomenon either way.