Did I miss something or have they ever addressed how the pagan gods fit into the Heaven & Hell, Angels & Demons etc. mythos? Are they just a *really* powerful breed of monster courtesy of Eve, or something else?
They're referenced in the bible multiple times, particularly in Exodus. "You shall have no other gods before me" not "I am the only god." The extended verse, which I don't remember verbatim, even has God admitting that he's jealous and simply doesn't want anyone worshipping the other gods.
As Dean would say: He's kind of a dick.
So whatever origin God has, chances are it's about the same for the other gods. Give or take.