[Act 3 Spoilers] Is **** actually *** ?

Is the Queen of Filth actually Atziri ? The clues are there, but she's supposed to be dead though right ? Are we to understand she actually survived the Vaal cataclysm under there and devolved into that thing ? Is the Atziri we fight in 1 then her "God" or legend form? Or simply a reflection in the atlas out of the mind of the Shaper or something, cause he doesn't know what actually happened to her ?

Queen of Filth has one pair, so unlikely.