In the developed cosmology of later texts such as the Bundahishn, the conflict of the two spirits is worked out across the whole of creation and the whole of time. Whatever Ahura Mazda makes good, Angra Mainyu answers with a counter-creation of harm: to life he opposes death, to health disease, to the useful animals the noxious ones, to truth the lie. The history of the world is the battleground of the two, divided into great ages, but the outcome is not in doubt, Zoroastrian teaching is emphatically not a balanced dualism of two equal and eternal powers. In the end the good creation triumphs, evil is defeated and rendered powerless, the dead are raised and the world is made perfect and immortal, a final renovation known as the Frashokereti.
Angra Mainyu's defeat is certain; his role is to be the adversary whose opposition gives the drama of existence its moral stakes. This vision of a cosmic struggle between good and evil moving toward a final victory has been widely discussed by scholars for its possible influence on later religious thought about the devil, judgement and the end of the world.