Zoroastrianism is one of the world's oldest religions that remains active. It is a monotheistic faith (i.e. a single creator God), centered in a dualistic cosmology of good and evil and an eschatology predicting the ultimate destruction of evil. Ascribed to the teachings of the prophet Zoroaster (also known as Zarathustra), it exalts a deity of wisdom, Ahura Mazda (Wise Lord), as its Supreme Being. Major features of Zoroastrianism, such as messianism, judgment after death, heaven and hell, and free will may have influenced other religious systems, including Second Temple Judaism, Gnosticism, Christianity, Islam, and Buddhism.
The most important texts of the religion are those of the Avesta. The religious philosophy of Zoroaster focused on responsibility, and did not create a devil per se. Zoroaster proclaimed that there is only one God, the singularly creative and sustaining force of the Universe, and that human beings are given a right of choice. Because of cause and effect, they are responsible for the consequences of their choices.
Post-Zoroastrian scripture introduced the concept of a contesting force to God called Angra Mainyu, or “angry” spirit. The concept of Ahriman, the Devil, was effectively a personification of Angra Mainyu.
Note: Their initial conception of God did not include their being a devil. There was good and bad (not good /not of God).
Fall of Man: As the Light and Love of God flows forth into creation, man’s misconceptions taint this purity. Our free will miscreates through distorted thoughts and emotions creating the miasmic ‘psychic plane’ and ‘astral cloud’.