Zoroastrian?..................
RE: What religion?//Zoroastrian?.................
As a matter of fact, all kidding aside, early Persia was the central site of the Zoroastrians and their belief in the gargantuan struggle between good and evil with the fate of the universe in the balance. Fewer than 120,000 of them are around to practice the faith today around the world.
The Jewish Sh’ma (God is One) opposes that duality. And its sister religion Christianity agrees.