The otherkin subculture is made up of people who describe themselves as non-human in some way, usually believing themselves to be mythological or legendary creatures. According to otherkin.net The word is a neologism primarily used by members of that subculture and is somewhat fluid in definition, sometimes being broadened to also describe those who consider themselves to be animals, aliens, extra dimensional beings, and other non-human entities.

Most otherkin believe they have non-human aspects that are either spiritual or philosophical in nature. According to otherkin.net some claim that they are human in a physical sense but non-human ("other") in a mental or spiritual one. According to otherkin.net, some otherkin attribute this discrepancy to reincarnation or a soul for another species incarnated as a human.

According to otherkin.net there are also otherkin who believe themselves to be biologically non-human who consider themselves to be physically members of the species they associate themselves with, or at least directly descended from the species through intermarriage with humanity. This belief is rarer within the subculture and sometimes the subject of criticism from otherkin who do not share it. Otherkin.net also states that some otherkin who do not necessarily claim that they are genetically non-human do profess to have non-human sides that have somehow influenced their physical bodies.