#to quote a japanese fanartist that I've been recommended: “Ultima-kun is too naughty!”

[zaziecurie]

"Ultima is boring, both as a character and even in his design-"

So anyway, Ultima's design is ever so interesting because besides the (implied) inspirations from Hindu religion and the Vitruvian Man (minus a second set of legs), his body seems to be a bit androgynous as his upper body is undeniably male while his lower part is a little more feminine.

I think if one looks at his final form, for example, you'll see what I mean.

Not only that, but his two sets of arms have differences between them: as pointed out by @millitron, the first set of arms are slimmer than the second set which are broader and even slightly larger hands.

(and here I was considering the big difference between the arms was the fact that the second set are a stand-in for Ultima's wings. If you notice, when Ultima is flying/floating, those arms are moving very subtly on his side, as if they're what allow him to use that ability.)

Kinda goes with this massive and lunatic attempt of a theory that fellow Ultima fans and I cooked up, where it's mention the unity of masculine and feminine divine energies and the notion of creation. Besides, of course, the fact that Ultima is the creator "god" of humanity.

And, in my opinion, a shout out to female!Ultima from Final Fantasy Tactics/FFXII.