A Triannon believer who joined D'Jamat's hijacking of Enterprise in 2153 but came to doubt his leader's cruelty and helped Archer to win the ship back.
Yarrick appears in the third-season Enterprise episode Chosen Realm, played by Vince Grant. He is one of a group of Triannon pilgrims rescued in the Delphic Expanse, who worship the builders of the spheres as the Makers.
The pilgrims carry organic explosives in their bodies and seize the ship so that their leader D'Jamat can use it against a rival sect at home. Yarrick, there with his pregnant wife Indava, follows orders but is troubled by his leader's ruthlessness, above all the demand that Archer choose a member of his crew for execution.
After Archer fakes his own death with the transporter, he appeals to Yarrick's conscience. Yarrick helps the crew to retake Enterprise, then returns home to find his world laid waste by the religious war.