>>3793458
This is pretty interesting. As you know, Siren is a Guardian Force, a summon. In FF9, the appearance of a summon is based on the memories of the local culture.

As far as Final Fantasy is concerned. Siren first came to us as a shapeshifting soul-sucking fiend in FFV. What's remarkable is that she can shapeshift based on memories a person no longer has. She shapeshifted into Krile, but Galuf had amnesia and had no idea who this girl was. Also, Galuf's sexuality is very confused at that point based on his interaction with Faris.

If they were sticking to FFV, then Siren's attack should inflict Zombie Status, not Silence. Zombie is pretty overpowered.
So clearly Siren's feathered appearance must mean she's a Genome from FF9. A Siren is also the figurehead of the Tantalus Theatership. Ruby is the only known female troop member, meaning the majority of female roles must have been played by men, such as Zidane. Kuja was also a fan of theater plays. Only, perhaps, because Kuja was attempting influence the culture to shape legends and sculpt a powerful Eidolon for himself.
That's right. He's your canary: Zidane in drag.
https://www.youtube.com/watch?v=4Diu2N8TGKA