Magus (called Zoroastrians in English) trace the beginnings of their faith to the teachings of Zoroaster, an Iranian prophet who lived and taught in the sixth century BC according to their traditional sources.
Within ancient Zoroastrianism, there were two major strands of belief : the orthodox Mazdaen and Zurvanites. The former maintained an ancient commitment to dualism: the idea of the world being the battleground between two forces: the eternal God Ahura Mazda and his adversary, the evil Angra Mainyu. The Ahura Mazda created the World in order to battle with his adversary. This power was exercised with subsidiary beings: the Holy Spirit, Spenta Mainyu and the six Holy Immortals, Amesha Spentas.
With these seven beings, each occupying one level of the seven-tiered heaven. The evil Angra Mainyu also has a patheon evil spirits on whom he calls to fight his cause. Whilst the structure of the cosmology seems highly patheistic, it appears that only the two Gods, Ahura Mazda and Angra Mainyu are eternal.
The other divine beings are expendable and many do indeed die in the course of the battle between good and evil. The apocalyptic of the Zoroastrians include the idea of a world savior who will bring about the final battle between the forces, the Good will ultimately be victorious. The victory and ultimate superiority of the Good is part of the claim made by some Zoroastrians that they are ultimately monotheists. In the midst of cosmic battle, human beings are created as potential warriors for Ahura Mazda, though they have the choice to reject this and side with evil.
Islam falls in the category of monotheistic creeds whose adherents believe in the Oneness of God and this is referred to as Tauhid in Islam.
This concept in Islam is based primarily on the fundamental principle that Allah alone caused all things to exist and He is the sole Lord of the universe; and its inhabitants without any challenge to His sovereignty. Nothing happens in creation except what He allows.
" اللَّهُ خَـلِقُ كُـلِّ شيء وَهُوَ عَلَى كُل شيء وَكِيلٌ
" Allah is the Creator of all things, and He is the Trustee over all things " Q39 vs 62.
He also says:
مَآ أَصَابَ مِن مُّصِيبَةٍ إِلاَّ بِإِذْنِ اللَّهِ
No calamity occurs, but by the permission of Allah " Q 64 vs 11. "
It is very clear that Magus (Zoroastrians) are purely unbelievers since they worship Ahura Mazda and Angra Mainyu other than the creator of the universe and for believing that there is another creator besides Allah. Allah says:
" إِنَّ الَّذِينَ ءَامَنُواْ وَالَّذِينَ هَادُواْ وَالصَّـبِئِينَ وَالنَّصَـرَى وَالْمَجُوسَ وَالَّذِينَ أَشْرَكُواْ إِنَّ اللَّهَ يَفْصِلُ بَيْنَهُمْ يَوْمَ الْقِيـمَةِ إِنَّ اللَّهَ عَلَى كُلِّ شَىْءٍ شَهِيدٌ
"Verily, those who believe, and those who are Jews, and the Sabians, and the Christians, and the Magus, and those who worship others besides Allah; truly, Allah will judge between them on the Day of Resurrection. Verily, Allah is over all things a Witness” . Q22 vs 17.