Thoughts on Siren?

[Nialle]

You didn't get to directly fight her in the story, it was more of a teaser battle. You fight her minions while she hangs out in the background. That just screams 'future content' to me, especially with how much effort they put in her design.

In the original FFXIV CE box art, there was some debate as to whether it was Siren or Garuda on the cover (if Siren, it would point to her being rather important). There was also some speculation then that she may have been the source of the Echo. Since we don't know what the original 1.0 plot was fully supposed to be, who knows if she once had a more important role in the story. The fact she has such a nice model seems to hint at such.