Hello all. I've been lurking for a while on these forums, and I thought I'd introduce myself by way of a theory.
It's all super-tenuous, as these things go, since there hasn't been much information relating to the God Beyond, but since I can't seem to find anyone else espousing this theory (I searched, but didn't see anything), I may as well start off here.
I'm probably wrong, but since I don't think the god beyond fits in with any of the shards, and by extension, with Adonalsium at all, I think the god beyond is same as the thing that "opposes Adonalsium", that Brandon mentioned at one point. Could potentially be an outsider (i.e. not from the cosmere universe); some sort of Cthulhu-esque being that is an anathema to the cosmere itself?
Just a thought.