Drex, son of Martok was a male Klingon who lived in the 24th century. He was the son of Martok, son of Urthog and Sirella, daughter of Linkasa. Drex was an officer in the Klingon Empire's Defense Force. After the uprising against his father in 2375, he was the only surviving child of Martok and Sirella.
Sometime in late 2370, Drex's father Martok had been captured by the Dominion while hunting targ on Kang's Summit on Qo'noS, and replaced by a Changeling infiltrator. The Martok changeling was so skilled that no one, not even his family, realized a switch had been made. (DS9 episodes: "The Way of the Warrior", "Apocalypse Rising", "By Inferno's Light")
In early 2371, Martok's changeling replacement led a large force to Deep Space 9. Drex was among the many hundreds of Klingons who visited the station. While there, he and several other Klingons accosted the Cardassian Garak and savagely beat him. Drex was later attacked by Lieutenant Commander Worf, as a way to get Drex's father to speak with him. Drex soon after departed the station when the Klingon task force left on its invasion of Cardassia. (DS9 episode: "The Way of the Warrior"; WizKids module: Attack Wing)
Over the next several years, Drex continued to serve the Empire, first during the conflicts with the United Federation of Planets, then in the Dominion War. During the war, the House of Martok played a vital role after the real Martok was rescued from Dominion captivity, with Martok eventually becoming Chancellor of the Klingon High Council in late 2375. (DS9 episodes: "The Way of the Warrior", "Apocalypse Rising", "By Inferno's Light", "Tacking Into the Wind")
The following year, when Morjod staged a coup d'état against Chancellor Martok, Drex assisted his father by commanding a Klingon ship. While communicating with his son during the coup, Martok was surprised to see Drex behaving like a mature and seasoned officer instead of a belligerent young man. Drex was severely injured during the battle on Boreth, and would have frozen to death had it not been for Emperor Kahless, son of Kahless. Drex recovered and was assigned to the IKS Gorkon as first officer. (DS9 - The Left Hand of Destiny novels: Book One, Book Two)
Captain Klag, commander of the Gorkon, found Drex to be barely competent, but an uninspired and uninspiring officer who had achieved his position only by nepotism. During the mission to taD, Drex was temporarily assigned as attaché to Governor Tiral, where he demonstrated a talent for administration and impressed the governor. When Tiral was reassigned to supervise the weapons development facility on HuDyuQ, Klag had Drex reassigned as liaison officer, reporting to Captain Ch'Targh. Drex attempted to appeal this reassignment to his father, but Martok refused to intervene. (TNG novel: Diplomatic Implausibility)
- The Path to 2409 disregards this account of Drex's death.
Following his father Chancellor Martok's death at the hand of J'mpok on stardate 70669.86 (2393), Drex counter-challenged J'mpok, accusing him of murdering Martok dishonorably. J'mpok's Arbiter of Succession, B'vat, rejected this claim, but Drex attacked J'mpok anyway. J'mpok easily defeated Drex, severely wounding him, but spared his life.
After J'mpok withdrew the Klingon Empire from the Khitomer Accords in 2399, he ordered all Federation citizens expelled from the Empire. Worf was allowed to stay to appease Drex, who would otherwise have pulled the House of Martok's warriors out of the Klingon-Gorn War.
- The same passages of The Path to 2409 that describe the above events also refer once to a son of Martok named "Drax", but in context this seems most likely to be a typographical error meant to refer to Drex: the same passage features other mispellings.
- DS9 episode: "The Way of the Warrior"
- DS9 novel: The Left Hand of Destiny, Book One
- DS9 novel: The Left Hand of Destiny, Book Two
- TNG novel: Diplomatic Implausibility
- ST novel: A Singular Destiny