Shrell is an ancient, defunct salarian deity belonging to a pre-Zamithian pantheon of gods predating the modern concept of the Wheel of Life, standing alongside such gods as Inanni and Uzuzap. Heavily rooted in demonology, Shrell was representative of the forces of destruction, disease and birds, and was typically represented by a triple-fanged blue egret-like creature, with skeletal wings and creeping tree roots (commonly misattributed as tentacles) for claws.
Borne from a collection of bizarre and archaic superstitions, Shrell's followers were partly responsible for the creation of the Ik'Zee Ma'Thukara (Book of Nothing's), along with a number of grotesque temples dotting Sur'Kesh's Maial Marshes. As of current day, most of these temples have either been destroyed or otherwise decayed to ruin, preserved only by the Salarian Cultural Act of 1784, and what little following remains is primarily represented by doomsday cults. Once such cult, known simply as "Shrell's Chosen," gained temporary notoriety as a terrorist organization before being destroyed by Salarian Special Tasks.
These days, Shrell's name is primarily used as an expletive, to be used in times of misfortune or surprise.
According to one krogan poster, "Shrell" is (or was) also a quarian name, to the amusement or discomfort of some salarians.