Warp Darkmatter was once Buzz Lightyear's partner and friend, but he had been secretly working for Zurg since his academy days as a double agent. He eventually began working for him full-time as "Agent Z." He is Rank II within the original Dominion XIII and a servant, though not a true member, of the 13 Seekers of Darkness. He commands the Hunter Stormtroopers.
His right arm is robotic (with various weapon attachments) and was grafted to his body after becoming Agent Z. Warp often takes on assignments for Zurg and is paid quite handsomely. (He owns a moon and a summer home.) Though Buzz has vowed to bring him in for treason, he retains some hope that there is still some good in him.
Within the ranks of the Dominion, Warp serves as the second-in-command to Zurg, and is a major antagonist in An Empire of Dreams and A Year of Misery.