Westrion, also called the Bird Man, is the God of Death according to Sacoridian religion. In art he is depicted as a man with the beak of a bird and black wings. Before dying, people believe they will hear the beating of his wings as he approaches to take their soul into the afterlife.
In The High King's Tomb readers learn that Westrion sometimes acts through a human avatar. The Gods cannot physically exist in the realm of humans, so if there is something that Westrion needs done he must act through a human. Karigan G'ladheon is his current avatar, although she has no memory of riding Salvistar and speaking with Westrion's voice to soothe the wakeful dead and prevent the destruction of her world. It appears that her avatar status is related to her Green Rider brooch, which was the first of the brooches to be made. A previous avatar appears to Karigan and explains that any who wear the first brooch, which provides the ability to touch death or "fade" between realms, may be called into service for Westrion.