Father to Worf and Kurn, and political rival to Ja'rod.
Mogh and his wife were killed in the Khitomer massacre of 2346, after following Ja'rod to Khitomer because Mogh suspected him of disloyalty.
Mogh's suspicions were correct: Ja'rod betrayed his people at Khitomer by providing secret defense codes to the Romulans.
Mogh was survived by his sons, Worf and Kurn.
Years later, in 2366, Ja'rod's son, Klingon High Council member Duras, falsified evidence in an attempt to conceal Ja'rod's actions and to implicate Mogh. Worf and Kurn challenged the accusations before the High Council, but council leader K'mpec was not willing to expose the powerful Duras family. (Sins of the Father [TNG])
Honor was restored to the Mogh family in late 2367 when the sons of Mogh agreed to support the Gowron regime during the Klingon civil war. (Redemption, Parts I and II [TNG])
In 2369, Worf investigated a report that Mogh had not been killed at Khitomer and that he had survived at a secret Romulan prison camp in the Carraya System. Although the camp was real, Worf learned from one of the inmates that the report was untrue. (Birthright, Part II [TNG])