Ignoring the problem of exactly where they come from, I'll throw out that Moloch, Belial, rakshasas, imps, djinn, and even the concept of devils and demons all come from other mythologies that were once (or still are) religions. And that's just off the top of my head. I'm sure there's more.
FWIW, despite my last couple posts saying that D&D shouldn't include real world religions, I'm completely fine with it borrowing mythologies that used to be religions. The devil* is in the details.
*non-denominational
FWIW, despite my last couple posts saying that D&D shouldn't include real world religions, I'm completely fine with it borrowing mythologies that used to be religions. The devil* is in the details.
*non-denominational