Something that's been bothering me about Aetherochemical Facility

[CyrilLucifer]

The artbook sheds a bit of light on this. The organic matter actually stems from the Triad Core, which is the entire reason you, Lahayorhm, and Thordan are there.
http://i.imgur.com/sR6bxtJ.png

Based upon what Unukalhai says, the chains that bind the Triad are what keep their bodies perpetually regenerated. I wouldn't be surprised is the fleshy material is a result, either from Sephirot's ability to regenerate/grow (after all, there are roots around Azys Lla), or one of the others' abilities that hasn't been told to us in a XIV context, yet. I'd put my bet on Goddess.

Alternatively, it could just be a buildup of whatever they're using to "regenerate" their flesh.