A Dahar Master was a Klingon warrior who had reached a legendary status among his peers and subordinates.(citation needed • edit)
Kor, Koloth, and Kang were all Dahar Masters. (DS9: "Blood Oath", "The Sword of Kahless", "Once More Unto the Breach")
According to the script for "Blood Oath",
Dahar was pronounced as "da-HAR".