6.4 patch speculation

[Cleretic]

Maybe it's the shadow dragon from the same game Golbez is from? Doesn't need to be the same dragon as Azdaja.

We will fight Golbez, he's gonna summon this shadow dragon, just as an enemy to beat without much story to it other than well he knows what dragons are through Azdaja, second phase is Golbez proper, we beat his ass and then we rescue Azdaja, maybe she has enough power left to live.

Sounds pretty straightforward to me. Don't put more thought into this than the writers.

I think you're grossly underestimating the writers. They don't just do 'here is the reference, now clap'; they recognize the value of said reference, but they do try to weave it into the world itself so that it matters a bit more than that--and crucially, so that it has any storytelling value at all to the people who haven't played the source game.

XIV Golbez absolutely, from a development and marketing perspective, has a shadow dragon because IV Golbez has a shadow dragon. But they very clearly intend it to be deeper than that; dragons are a relatively special thing in XIV, so he can't just have one with no explanation, so they wrote the plot around him having Azdaja to lead into his shadow dragon who, now that we've seen it in part, clearly resembles Azdaja. If the shadow dragon was just going to be a nothing-special second phase gimmick they wouldn't have put it in the art (Golbez is a cool enough design and enough of a hook by himself if all you want is IV nostalgia and 'here's the bad guy'), so the fact that it's in the art means that it's somehow worth teasing and foreshadowing.

But speaking of the art, I can't really get behind SannaR's mention that the body doesn't resemble Azdaja. We just don't see enough of it to be sure on that; the background outside of the dragon, Golbez and the throne is too blurry, so I can't really say 'there should be wings there and there aren't'. All we've really got are the head--which as said, resembles her in the horns and the most curious thing to me is having both eyes--and the hand and part of the body on the other side. The hand's the right shape, the body's the right size, so it's mainly the texture that's wrong there--and I could easily see that being maybe what she looks like without feathers, or in armor, or a void-corruption carapace or something.