Who is Zoroaster in the nonfiction book, Thou Art That?

Zoroaster was a Persian prophet living either ca. 1200 BCE (making him Homer's contemporary) or 600 BCE, Zoroaster (also known as Zarathustra) teaches that there are two gods, one good and the other evil. On the last day, after the "Reckoning of Spirits" (Armageddon), Zoroaster will be incarnate a second time, wipe out all evil, and usher in an eternity of peace, light, and virtue.