In the shardcast " The set, trell, and paalm" many things are discussed and I happen to be relistening to wax and wayne. They reference the faceless immortals many times implying it is just the Chandra. However in the shardcast, it's discussed that they are something else entirely?
I have to listen infrequently and when I'm able to. Let me know if I am missing anything, I'd love to discuss. I also know we have very little to go on regarding them so this may be a short discussion.