The Chakuun were a semi-insectoid species that were conquered by the Tholians sometime prior to the mid-23rd century. As a client race of the Tholian Assembly, the Chakuun were used as shock troops by the Tholian military.
During the Tholian-Federation conflicts of the 23rd century, the Chakuun frequently carried out devastating strikes against Federation colonies. In 2254, contact between the Chakuun and Starfleet at Theta Kalyb led to a cessation of hostilities between the Federation and the Assembly, once the two powers differing interpretations of territorial alignment were understood. (Star Trek: Early Voyages)