This touches upon a very understandable but important misinterpretation of Zoroastrianism. There really isn’t any other god but Ahura Mazda in the Zoroastrian faith. It is the beginning and the end, the supreme being of pure good. It has manifestations and powerful servants, but these are not gods, in the same way that the Christian God has supernaturally powerful servants that can level cities and traverse great distances; we call these angels and archangels, but just because they have immense supernatural power doesn’t make them equivalent to God or even lesser gods themselves.

The same is true of Ahura Mazda, there is no force equivalent, even its greatest enemy is not the God of Evil, but rather just the manifestation of evil that Ahura Mazda is destined to destroy, once again analogous to the Christian God having the ultimate enemy of Satan, but Satan is not a god in his own right.

For a more in-depth look at Zoroastrianism (and Persian culture in general), you can find a lot of interesting cultural information online at Iranica Online. For a more in-depth analysis of Ahura Mazda, the supreme being of Zoroastrianism, that page is here: https://iranicaonline.org/articles/ahura-mazda