Otherkin largely identify as mythical creatures, with others identifying as creatures from fantasy or popular culture. Examples include: angels, demons, dragons, goats, elves, fairies, sprites, aliens, and cartoon characters. Many otherkin believe in the existence of a multitude of parallel universes, and their belief in the existence of supernatural or sapient non-human beings is grounded in that idea.

With regards to their online communities, otherkin largely function without formal authority structures, and mostly focus on support and information gathering, often dividing into more specific groups based on kintype. There are occasional offline gatherings, but the otherkin network is mostly an online phenomenon.

Some otherkin (such as elvenkin) state they are allergic to iron (and products of modern technology), while others (such as dragonkin) state that having no allergies is a sign of otherkin condition. Some otherkin also claim to be especially empathic and attuned to nature. Some state to be able to shapeshift mentally or astrally, meaning that they experience the sense of being in their particular form while not actually changing physically.

The therian and vampire subcultures are related to the otherkin community, and are considered part of it by most otherkin, but are culturally and historically distinct movements of their own, despite some overlap in membership.

Otherkin are a subculture who socially and spiritually identify as partially or entirely non-human. Some of them surmise that they are, either spiritually or genetically, not human; however, this claim is unsubstantiated. This is explained by some members of the otherkin community as possible through reincarnation, having a non-human soul, ancestry, or symbolic metaphor. Some scholars categorize this identity claim as "religious", because it is largely based on supernatural beliefs. Adherents more typically deny the religiosity of otherkinism, referring to it instead as simply a congenital condition, or a metaphysical state of being.

Species dysphoria is the experience of dysphoria, sometimes including clinical lycanthropy (delusion or hallucination of one's self as an animal) and dysmorphia (excessive concern over one's body image), associated with the feeling that one's body is of the wrong species. Earls and Lalumière (2009) describe it as "the sense of being in the wrong (species) body... a desire to be an animal". Outside of psychological literature, the term is common within the otherkin and therian communities. The phenomenon is sometimes experienced in the context of sexual arousal to the image of one's self as an animal.

"Species dysphoria" is informally used mainly in psychological literature to compare the experiences of some individuals to those in the transgender community. Otherkin and therian communities have also used it to describe their experiences.

In a 2008 study by Gerbasi "et al.", 46% of people surveyed who identified as being in the furry fandom, (usually defined as a person who enjoys anthropomorphic animals, occasionally to an almost obsessive degree), answered "yes" to the question "Do you consider yourself to be less than 100% human?" and 41% answered "yes" to the question "If you could become 0% human, would you?" Questions that Gerbasi states as being deliberately designed to draw parallels with gender dysphoria, specifying "a persistent feeling of discomfort" about the human body and the feeling that the person was the "non-human species trapped in a human body", were answered "yes" by 24% and 29% of respondents, respectively. Likewise, these studies support the fact that the therianthropic, otherkin and furry communities are very similar in nature and are often interconnected.

As described by those who experience it, species dysphoria may include sensations of supernumerary phantom limbs associated with the species, such as phantom wings or claws. Species dysphoria involves feelings of being an animal or other creatures "trapped in" a human body and so, is considered different from the traditional definition of clinical lycanthropy, in which the patient believes they have actually been transformed into an animal or have the ability to physically shapeshift. However, some cases that have been labeled as "clinical lycanthropy" actually seem to be cases of species dysphoria, involving persons who have no delusion of transformation but instead have feelings of being in some way a non-human animal, while still acknowledging they possess a human form. Keck "et al." propose a redefinition for clinical lycanthropy that covers species dysphoric behaviours observed in several patients, including verbal reports, "during intervals of lucidity or retrospectively, that he or she was a particular animal" and behaving "in the manner of a particular animal, i.e. howling, growling, crawling on all fours". Keck "et al." describe one patient as a depressed individual who "had always suspected he was a cat" and "laments his lack of fur, stripes and a tail". Except for the persistent feeling of being feline, the patient's "thought processes and perception" were "usually logical".