A rogue member of the Hierarchy who abducts Captain Janeway in 2378 and blackmails the Doctor into impersonating Voyager's crew in order to steal the ship's warp core.
Zet appears in the seventh-season Voyager episode Renaissance Man, played by Andy Milder. Having broken away from the Hierarchy with his partner Nar, he intends to make his fortune by selling a Starfleet warp core.
He captures Janeway and the Doctor aboard the Delta Flyer and sends the Doctor back alone with orders to deliver the core or see the captain killed. Monitoring him from a distance, Zet pushes him through a string of impersonations of Janeway, Chakotay, Torres and others.
Once he has the core, Zet breaks his word and decides to keep the Doctor as well, valuing his holographic talents. His greed alienates Nar, and with the arrival of Tuvok and Paris his scheme collapses and the core is returned to Voyager.