The best way to answer “what is otherkind” seems to me: an involuntarily experienced identity phenomenon, based upon the collective experiences and thought processes of nonhuman identity within a human form.
Makes no assumptions as to the roots of each person’s take, spiritual or otherwise, but outlines the basics. That it can’t be induced or chosen, and that it constitutes an awareness of and some degree of separation between the human body and the nonhuman person inside of it.
It is not a strong connection to anything or a vehicle for trauma, it is what you are and nothing less than that.
This is basically how I’ve been putting it, “an involuntary nonhuman identity” and “an ontological phenomenon”. Though i guess the latter only applies to spiritual otherkin, but I’m unsure.
I think it could apply to all. How exactly a human brain could develop so intensely and “completely” along the lines of a nonhuman, without metaphysics getting involved, sounds like it would make for an interesting philosophy class.
It would, tbh. I think the leading non-spiritual explanations are mental quirk not worth pathologizing or, tracing it back to an unconscious adaptation due to trauma or as a byproduct of mental illness/general brainweirdness. Both of which open up some pretty interesting discussions of psychology themselves. Overall you could get into topics in psychology, sociology (I think? If you include nonhumanity in cultural contexts.) and philosophy depending on which hole you’re most suited to jumping down, lol.