T'nag was an old enemy of the Klingon warriors Kor, Koloth, and Kang. The three Klingons set out against T'nag's army of 40 legions, but by their final, glorious all that remained were three legions. The emerged victorious against overwhelming odds, killing T'nag and feasted on his heart. (DS9: "The Sword of Kahless")
Kor once held the Korma Pass against T'nag's forces. (DS9: "Once More Unto the Breach")