The Right of Vengeance was a traditional Klingon matter of honor that was claimed when a Klingon sought revenge against another. Any Klingon, even one who had received discommendation, could claim it.

After Duras murdered K'Ehleyr in 2367, Lieutenant Worf claimed Right of Vengeance against Duras. Initially, Duras rejected the challenge, but subsequently accepted it when Worf declared that K'Ehleyr was his mate. Worf then killed Duras in hand-to-hand combat. (TNG: "Reunion")

In early 2368, when it was discovered that the House of Duras had conspired to destroy the honor of the Mogh, Chancellor Gowron offered Worf the life of Toral in exchange for his family's misdeeds against the House of Mogh. Worf declined because Toral was a boy who had done nothing, a decision he regretted a few years later. (TNG: "Redemption II")

According to Kor, "A Klingon who denies himself the Right of Vengeance is no Klingon at all." (DS9: "The Sword of Kahless")

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The commander of a Romulan warbird claimed the "Right of Vengence" after the interstellar alien Gomtuu destroyed its sister ship. It is unknown whether this is a figure of speech or if it implies a more ritualistic matter of honor similar to Klingon law. (TNG: "Tin Man")