I think that image may actually be ASURA, the Summon known as a multi-armed woman holding a bunch of swords, in FFIV she was the Queen of the Eidolons. In fact, I think the "things" coming out of her back are actually her ARMS.
It would hold up to Gabranth's "Lady of Blades" comment and, if we assume that she was a Primal/Goddess worshipped by the Hrothgar, they may have ORIGINALLY envisioned her as a Hroth, but if Gabranth is planning on using her against us, she may have more humanoid features, as we know that the appearance and personality of a Primal changes depending on the view and intentions of the Summoner.