Xantriph was a beholder living in the Temple in the Sky, a strange flying hollow rock over Teshendale. Informed by his spies of the strange place, Manshoon investigated personally, hoping to find powerful magic. Instead, he discovered the beholder Xantriph. The two canny individuals joined forces, claiming the rock was a conduit to the gods. Banite priests flocked to the place where Xantriph instructed them all to do as Manshoon commanded, joining the Zhentarim and leading them away from the decadent High Imperceptor of the church. However, in order to do this, Manshoon and his magelings had to pledge fealty to Bane, promising to lead the faith to even greater heights of power than the weakening High Imperceptor had. Furthermore, Manshoon promised control of the priesthood and Zhentil Keep to the beholders, or so it seemed.
The plot was ruined when, in 1350 DR, the adventurers known as the Knights of Myth Drannor discovered the Temple and in exploring it they found Xantriph. The Knights soon fought the evil monster and killed Xantriph.