Nancy Sthili was a Starfleet crewperson serving aboard Deep Space 9 in 2376. In April of that year, Sthili was on duty aboard the USS Defiant when the station was attacked by a rogue Jem'Hadar strike team. The Jem'Hadar were defeated, but at the cost of the life of Defiant's commanding officer, Commander Tiris Jast. Sthili, like many of her shipmates, seemed to feel an irrational sense of guilt towards Jast's death. (DS9 novel: Avatar, Book One)