Yarrick was a Triannon male who was second-in-command to Pri'Nam D'Jamat. He was married to Indava.
In November 2153, Yarrick came aboard the Earth Starfleet vessel Enterprise NX-01 following a faked distress call from his starship.
Yarrick had doubts about D'Jamat's plan to hijack Enterprise, believing it was not right to repay kindness in such a way. After learning about his wife's pregnancy, and reluctant to bring a child into the world when it would just become another soldier, he eventually sided with Captain Jonathan Archer, helping him take back control of the ship.
Yarrick programmed the environmental control from a console in the situation room on the bridge allowing Doctor Phlox to release an airborne agent which neutralized the Triannon organic explosives. During the takeover of the bridge he handed a phase-pistol to T'Pol.
Yarrick and Indava later boarded Shuttlepod 2 and were brought to the surface of Triannon where they saw the destruction of the civil war. (ENT: "Chosen Realm")
