User blog comment:Vitorriq/who created the pagan gods/@comment-1975828-20160825233109

Maybe the pagans ARE monsters, as Dean and Sam consider them to be. However, they have their own community, and were worshipped and gained power through worship. While other monsters became merely bedtime stories for children, these pagans, at one point, were successful in earning the loyalty and respect of mankind, until most of them lost their followers to Jesus, as the Carrigans bemoaned once.

Which leads me to believe that they could be hybrids of some kind, descendants of the Mother of All, maybe?