It is generally accepted that Husayn ibn Mansur al-Hallaj (d. 922) was the first Sufi author who admired the Devil (Iblis) as an esoteric saint, the most perfect model of monotheism and an unapologetic lover of God. In his work Kitab al-Tawasin, al-Hallaj declared Iblis’s rank to be above that of Moses and only equal to the Prophet Muhammad. al-Hallaj’s infatuation with Iblis had a tremendous influence on the writings of other Sufi authors such as Ahmad al-Ghazali (d. 1123), and ‘Ayn al-Qudat Hamadani (d. 1131) in the following centuries. Yet there has been little study as to what set of doctrines influenced him to become a passionate defender of the Devil and motivated him to make such antinomian claims about a figure that Qur’an consider to be the ultimate enemy of man and God. This paper will attempt to demonstrate that from the beginning of 9th century to the middle of 10th century, there existed several seemingly unrelated but prominent religious movements in the heartland of Abbasid Caliphate which promulgated the doctrine of sympathy and love for the Devil. These religious movements included various Shi‘a exaggerators (ghulats) such as the followers of Muhammad ibn al-Shalmaqani (d. 934), Zoroastrian sects such as the Zurvanites who were influenced by the writings of Zoroastrian priests such as Mardan-Farrukh (d. after 830), and most importantly, the Sufis who, in various degrees, propagated their affinity for the Devil under the relative intellectual freedom of the Abbasid Caliphate in the 9th and early 10th century. Most of these Sufis such as Sahl al-Tustari (d. 896), Junayd al-Baghdadi (d. 910), and Abubakr al-Shibli (d. 946) were either teachers or colleagues of al-Hallaj who also shared his passion for Iblis. Therefore, this paper will argue that it was in this multi-confessional milieu of antinomian religiosity that al-Hallaj was able to formulate and propagate his dogma concerning the divine nature of the Devil as an uncompromising monotheist and the true lover of God.