Captain D'Chok was a Klingon member of a Great House who served as an officer in the Klingon Defense Force during the mid-23rd century. He commanded a D7-class battle cruiser.
In 2259, D'Chok's cruiser arrived at Cajitar IV to commence the Klingon period of control over its dilithium mines. He detected the USS Enterprise apparently pursuing another Federation starship, NCC-1279, out of the planet's rings. As he prepared to engage, the Enterprise destroyed the other ship. D'Chok proceeded to hail the Enterprise and demand an explanation.
D'Chok was skeptical of acting captain Spock's claim that NCC-1279 was a rogue vessel attempting a false flag attack. Given D'Chok's declaration that he could "know a man's truth only when [he] look[s] into his eyes, face-to-face," Spock proposed that they discuss the matter personally over a barrel of bloodwine. Amused by the notion of a Vulcan drinking bloodwine, D'Chok agreed. On the surface of Cajitar IV, Spock managed to form a bond of camaraderie with D'Chok and his crew, and broker a peace treaty to defuse the crisis. (SNW: "The Broken Circle")