Urthog was a male Klingon born in the middle of the 23rd century to a common family in the lowlands of Ketha Province. Like fourteen generations of male family members before him, Urthog enlisted in the Klingon Defense Force as a common foot soldier, serving well and forming a small group of friends along the way.
Urthog later retired, having never achieved officer status, but had high hopes for his son Martok, who he wanted to become something better than a foot soldier. It took a great deal of effort, but Urthog found an old friend willing to sponsor Martok for enlistment. Everything went according to plan, with Martok passing the entrance exam with flying colors and went before the oversight council, but his applications was suddenly rejected by one of the council members; Kor, who believed it was inappropriate for a man without noble blood to become an officer, and to Urthog's embarrassment and Martok's everlasting shame, Kor struck his "mark" against Martok's record, preventing Martok from ever getting into the armed forces. (DS9 - The Left Hand of Destiny novel: Book One; DS9 episode: "Once More Unto the Breach")
In 2345, Martok signed on as a civilian laborer aboard General ShiVang's flagship and was later able to get a battlefield promotion two years later after a Romulan incursion which started his rise to power, but Urthog died sometime before that glorious day. (DS9 - The Left Hand of Destiny novel: Book One)
Later, Martok achieved the highest post in the Empire; Chancellor of the Klingon Empire, though quickly found his position challenged by Gothmara, daughter of Kultan and her son (secretly by Martok) Morjod; the latter of which made a point of insulting Urthog's memory. During the crisis, Martok had a near-death experience, due to injuries he sustained in combat. Near-comatose, Martok was visited by his father's spirit, who gave him the emotional support and strength necessary to continue to fight Gothmara. Martok learned that Urthog had been a member of the Katai, a group dating from the Hur'q invasion that strove to preserve Klingon valor. (DS9 - The Left Hand of Destiny novels: Book One, Book Two)