Wobblegong

The reason I can say my lady's assigned fursona is some kind of firebird is because of a neat AU I made up with my friend. The excessively concise/facetious summary is "it's because of giant robots".

A few years ago now one of my pals who is both fun to RP with and also treats worldbuilding as a free action (like me!) stumbled into a silly, tropey mess of an AU premise: what if we took a mecha anime setting and then put our characters down slightly to the side of the camera's view, so to speak? Both of our FFXIV characters we were going "hmm..." over are not suited to being mecha anime protagonists, but they'd fit supporting character roles perfectly. And both of us are the kind of person who think it would be fun/ny to work out a mecha-AU just to ignore the robots and the protagonist-ly action and instead inspect life as one of the people involved in making giant mechs.

(We were correct, it's a blast.)

Anyways for a lot of the setting we decided not to reinvent the wheel and just run Eorzea through a mecha-anime filter. Good way to cut down on having to name landmasses and geopolitical entities, but it was enough to warrant refinangling backstories and the like to better fit the setting. I took the opportunity to get really self-indulgent and ironed out Keim's family tree so hard that I arrived at "oh, the reason her mom ditched the family and didn't just go back was because her family was... a village of bird-cultists?" Something in the vein of FFXIV-canon auspices, I think, but yeah there's a hidden village of people worshipping/tending to a really old supernatural/magical bird, and part of its deal is it blesses them somehow. Basic magical-animal-guardian shit really, but because nobody can stop me I suggested the magic didn't completely skip Keim despite "mixed" heritage/not being born within blessing radius, which informs her magical skills in this AU (animal knack. she can talk to and control animals. it's just animal knack).

And double for fun, in this AU Keim is a very brilliant scientist working for the kind of outfit that makes giant mechs, so she regularly works with very fancy/fucked up magitek. I posited that polymorph-type magic would probably go awry if applied to her on account of standard polymorph magic NOT taking into account weird magic animal blessings. We haven't RPed it out as of this chost but I had an evil chortle over the premise of Keim trying some minor polymorph magic and turning into... you may have guessed this... phoenix-y birdsona.

ps. in main canon Keim has a chocobo, Synginebb. A lab rat who lives alone in an urban townhome would be hard-pressed to keep a bird that's 10 feet tall and needs to run a lot, so for the AU I decided Synginebb is a (Meracydian) berryfowl, the mecha-AU equivalent of Pipile cumanensis AKA the blue-throated piping guan: