The things you seem to be think of in terms of "otherkin" seem to me to be more clearly defined as therianthropy, soul-bonding, and, uh, "furryism?", which are almost like somewhat seperate subclasses that could be termed "otherkin" but are by no means generally representative of the whole group. Sort of like calling someone who was "mid-continuum" multiple. It could be seen as correct but in more of a technical sense than anything else.

If you consider spirituality, religion, and animism to be "mythology" then I suppose what I would think of as otherkin would fall under your description of people associating themselves with fictional characters.

At any rate though, what you are saying makes sense. I suppose I just tend to think of it, especially involving concepts of multiplicity, more along the lines of having a new person "arrive" from outside the system, bearing with them their own set of memories and identity.

That's the way most all of us who would call ourselves Otherkin came to be here. Not because of association but because that was a part of our identities before we ever arrived to share this body. At least a few of the others in this situation could leave again and remain existant and lead their own former life in whatever world they came from at any time if they so chose.

I don't think I am unique in this, but at the same time, I am also sure that not all kin-others in multiple systems are the same way, and I'm also sure that not all "walk-in" otherkin are the same way. That's part of why I find the subjective interactions so fascinating.