Our Otherkin FAQ explains the concept of "kintypes," which is basically "what you are on the inside" and can be anything from an animal to a mythical creature or fictional character. Many "therians," "otherkin," and "fictives," like us, incorporate this belief into their already-existing religious practice and leanings. Others see it not as a mystical truth but a goal, an ideal, or simply an explanation for "why I feel this way" that rings true to them.
Either way, for those who feel they may be otherkin finding one's kintype is a process of self-discovery, similar to (but distinct from) finding a totem or a patron saint. You don't have to stick with the same one forever, and just because something strikes you as "cool" doesn't mean that it necessarily calls to you, holds personal meaning for you, or feels deep down like it's what you've always been all along.
Having said that, if we  got to choose our own kintypes instead of dealing with that messy self-discovery business, here's what we all would have come up with!
... and what parts of our real nature each choice denies.
Actual kintype: Kitsune, fox-woman, possessing fox spirit, aspect of Inari Ōkami
Her choice: Yuna from Final Fantasy X and X-2. I haven't played either game the whole way through, but from what I gather she's a summoner miko who's raised in a fundamentalist church, then finds her own voice (and it's a lovely singing voice, too). Plus she'd have an easier time of blending in to human society ... because she is one!
Actual kintype: Lightning from Final Fantasy XIII, as a goddamn feathery raptor the size of a swan
Her choice: I'd be a fucking xenomorph. Acid blood, armour skin, rapid movement and screaming fury. No need to confront myself, come to terms with a nature I'm horrified by, realize the effect that I'm having on people I care about, and try to find out who I am when I'm not jealously guarding my boundaries. Just tearing, devouring, spreading. Fighting the Alien series' real villains, the rapacious human corporations, without being personally betrayed by human society. And finding out my whole life was a lie.
Actual kintype: Either Rei Ayanami from Neon Genesis Evangelion or one of her many, many clones
Her choice: Something like a tachikoma. If I have to exist in public, I want others to see me as a machine, the way that I see myself. Because I don't know how to be a person, and I am uncomfortable when people try to relate to me as one.
(Claire: We had to poke Rei to get her to write more than a sentence, there.)