Ormazd is the God of Light and brother to the God of Darkness, Ahriman.
In the beginning, only Ormmazd and Ahriman co-existed alongside one another, both of them representing light and darkness respectively. Ormazd once had control over the universe, having established both the Ahura and the City of the New Dawn granting them both of his own powers during this period.
Until his brother learned how to convert the heart of humans with his dark powers. Due to the ease of dark intent in human hearts, the tables quickly turn in Ahriman's favor, with him gaining more power from each follower that he gained. Ormazd had then retaliated by attacking his brother and cause an all-out war between the two gods. Understanding his power growing from his followers, Ormazd began striking them down before they could further empower Ahriman.
This strategy succeeded to an extent and by the time Ormazd tired, only a few of Ahriman's select were left — the Hunter, the Concubine, the Warrior, and the Alchemist. Using the last of his taxing powers, he sealed the four corrupted followers and Ahriman into the Tree of Life.
e then entrusted the Ahura to protect the Tree of Life to prevent Ahriman and his corruption from returning into the world before disappearing into the cosmos.
In Zoroastrianism, Ormazd (also Ahura Mazda) is a divinity exalted by Zoroastrians as the one uncreated Creator, hence God.