Board Thread:Mortal Kombat X/@comment-97.116.170.197-20160205021235/@comment-12973094-20160207151013

I agree with you, but I still have another theory too:

Shinnok could have been the Elder God of Life or something like that. Then he became corrupted during the War with the One Being, and when he was cast out from the heavens, Shinnok adopted new powers, related to the Netherrealm, which became his own realm.

Or he's like a couterpart to Hades, God of the Underworld, with references from Satan.