In order to evaluate what we cannot understand, there must be some level of objectivity. Though the notion of a person who firmly believes they are, at their core, a non-human entity seems absolutely bonkers to most.
Those people – the ones who identify as non-human – call themselves ‘Otherkin.’
The history of the Otherkin movement began on the internet. With technology came a way for people everywhere to communicate with each other indiscriminately. Otherkin were no exception. Things that an Otherkin may identify as include animals, mythological creatures, demons, angels, or combinations of any of those and other non-human or non-existent entities.
It’s always a thorny venture to comment upon what someone identifies as. It’s also a thorny venture to discern how to tell the difference between someone who truly feels some degree of desperation in their identity, and someone who feels like they aren’t getting enough attention for being a special snowflake. Nevertheless, Otherkin have built their own communities, and maintain a presence on the internet, and, to some degree, offline.
An example of a modern day, non-Tumblr platform for Otherkin is The Otherkin Community – it has forums, a link to a Wiki, and has moderating rules for respect.
In closing, there are humans who aren’t humans. And they’re just doing their thing. Know more.