Full Idea
Zoroastrianism saw the world as a cosmic battle between the good god Ahura Mazda and the evil god Angra Mainyu.
Gist of Idea
Zoroastrianism saw the world as a battle between good evil gods
Source
report of Zoroaster (The Gathas (seventeen hymns) [c.900 BCE]) by Yuval Noah Harari - Sapiens: brief history of humankind 12 'Battle'
Book Reference
Harari,Yuval Noah: 'Sapiens: a brief history of Humankind' [Vintage 2014], p.247
A Reaction
Hm. This contradicts the impression I had gained that it was monotheist.