Zach: This oracular demon can answer all questions concerning matters in the past, present, and future. In the edition of the Sworn Book translated by Joseph Peterson, Zach is named as a minister of the demon Habaa, king of the spirits of Mercury.
In accordance with his mercurial nature, Zach is said to manifest in a form that shifts and shimmers like glass or white-hot flame. He has a special awareness of all secret thoughts and deeds, and he can reveal the secret affairs of both mortals and spirits. He also provides good-natured familiar spirits.
According to the text, he can be compelled in the names of Michael, Mihel, and Sarapiel, the angels thought to govern the sphere of Mercury.