Prior to the Krogan Rebellions clan Cruack were a large and powerful clan, easily the rival of Korwun and Vynchar, but lost a large number of their troops in an ill-fated attack on the turian colony of Palus. Information on Palus obtained by Cruack spies had lead Battlemaster Cruack Grenk to believe the colony was a relatively-undefended sanctuary for the families of a number of high-ranking turian military leaders. Hoping to crush the turian spirit by assassinating the families of their leaders, Grenk lead the majority of his clan on a raid on the planet, only to discover that it was a trap laid by the turians. The entire colony was abandoned and empty and, as the invading Cruack forces attempted to flee, a turian cruiser hidden behind the planet’s moon annihilated the colony with a redirected asteroid.
Since the end of the Rebellions clan Cruack has been forced to ally with clan Korwun for protection. Despite their reduced numbers the Cruack are known for their ferocity in battle and their loyalty to their allies.