In another book of theirs, Kitab-e Zand, they refer to a battle between Ahriman (the devil) and Ahura Mazda (the Lord). This battle will rage for a long time, and for most of it the army of evil will be winning, but will never be able to terminate the army of goodness. As the situation becomes intensely difficult, God will send the saviour and the battle will continue for an additional 9000 years. The saviour will ultimately defeat them, and then all of humanity will be prosperous, happy, and will live peacefully.
In this sense, the Zoroastrians have the same general principle as other religions, that there will be much difficulty and corruption before prosperity, albeit the specific details differ between the faiths.
Kitab us Zind the religious book of the Parsis mentions about the end of Injustice and the victory of the righteous as follows: “There is a constant conflict between the armies of Ahreman and Yazdan for supremacy in the land. Though mostly Ahreman is victorious yet Yazdan is never fully vanquished such that neither he nor his progeny remain. In difficulties, he receives help from God (Avarmazd) as he is His son. Thus, their war will go on for 9000 years until finally Yazdan receives a great victory. Ahreman’s army will be defeated and no trace of his followers will remain in the heavens and the earth. Following the complete defeat of Ahreman and the conclusive victory of Yazdan the world will progress towards its perfection and happiness. Men will enjoy lasting peace and victory.”
In the book Jamsabnaamah it is mentions that: “In theland of Taziyaan, from the progeny of Bani Hashim, a person will rise. He will possess a large head, a husky voice, and long shins. He will follow the religion of his ancestors. He will come to Persia with a big army. He will enliven the land with justice and equity.”
At another place it is mentioned: “The Great Reformer will spread the religion in the Land. He will eradicate poverty and scarcity. He will successfully support Yazdan against Ahreman. He will lead humanity through an ethical, moral and intellectual revolution.