A Klingon Dahar Master and comrade of Kang and Kor who was still spry, steely and stealthy after more than a century's service in the Klingon military. Curzon Dax had called him 'D'akturak' 'ice man' for his toughness in negotiating when they squared off against each other.

As the captain of the I.K.S. Gr'oth who faced James Kirk at Space Station K-7 during the Sherman's Planet affair in 2268, he once defeated T'nag and his army with only colleagues Kang and Kor, according to Kor's tale in 2372, later feasting on the leader's heart. He personally attacked T'nag's flank with only a disruptor and a bat'leth, killing two dozen men; for at least Koloth, it was out of vengeance.

In 2269, while pursuing trader Cyrano Jones, Koloth's vessel uses a dangerous new weapon that projects a stasis field effect which disrupts the targeted ship's engines and weapons, rendering them powerless. Unfortunately, this weapon is a huge power drain and cannot be maintained for long, nor against more than one vessel. It is also useless against transporter beams, as Koloth finds when Kirk has giant tribbles beamed aboard his cruiser!

Death came heroically with Kang in 2370 while fulfilling their blood oath with Kor and Dax against the Albino, the marauder who had killed all the Klingon trio's firstborn sons in 2290. He had no respect for Kor's drunkenness but his demeanor even affected Odo and Kor vowed to sing of his valor forever.