Otherkin is a sort of catch-all term for people who feel that, in some way, they are not entirely human.
In a sense, weres are a kind of otherkin, but in general, otherkin refers to people who believe they are fae
, or vampire, or another nonhuman, possibly mythic
type of creature.
There is some crossover between the therianthrope
and otherkin communities, and often while researching one, you'll find the other.