Amen: In the Ars Theurgia, Amen is named as a demon in the hierarchy of prince Usiel. It is tempting to relate this demon to the ancient Egyptian deity Amen (also spelled Amon), but there is no indication in the text that the two are connected.
Amen and his master Usiel both serve the infernal emperor Amenadiel, and Amen's name may relate more to this superior demon than to any ancient deities. Through Amenadiel, he is affiliated with the west. Regardless of the origin of this name, Amen is reputed to be a chief duke who holds sway over forty lesser spirits. He has the power to reveal hidden treasures and he excels at hiding things himself so they may not be discovered or stolen. He serves his master during the hours of the day. His name is sometimes spelled Amon, although the Ars Theurgia does not seem to relate him to the Goetic demon of the same name.
SOURCE:
The Dictionary of Demons written by Michelle Belanger