The Chakuun were originally a minor but warlike race. The Chakuun were annexed by the Tholian Assembly "four hundred cycles" before 2254, and offered their services as soldiers. The Chakuun eventually became an elite military force within the Assembly.
The Chakuun shared the Tholian understanding of a dynamic, shifting cosmos. In 2254, when the Tholians realigned their territory to compensate for the shifting of stars, the Chakuun launched an offensive against the Federation, destroying colonies on Jubal and Theta Kalyb that they regarded as invasions. At the Battle of Theta Kalyb, the Chakuun succeeded in destroying the Nelson-class scoutships USS Brazzaville and USS Providence as well as the Miranda-class USS Achilles. In previous encounters, the Chakuun destroyed the colony of New Milan and a starship Claire Thorn was serving on. (EV comic: "The Fallen")