Xander Torralyn d'Sivis was the navigator and scribe for The Couriers (Orien Expedition No.2), thought to have been lost in Khyber. That is partly true, the Couriers as a whole were lost to Khyber, but both Xander and Dragomir survived and were later picked up by the Razor Wind.
Xander now acts as an advisor to Valkhoth Peacekiller, and his contributions are very highly valued. His maps have been of immense help.