In the mirror universe, Zek was a Ferengi male who lived during the 24th century. In 2374, Zek approached the Terran Rebellion's leader Miles "Smiley" O'Brien on Terok Nor with the offer of a Romulan cloaking device for the Defiant. O'Brien had harshly dismissed the "doddering old Ferengi" as "a worthless whining prune." However, Zek was able to deliver on his promise and secured the cloaking device for the rebellion. This gave the rebels a major tactical advantage over the Klingon-Cardassian Alliance after it was installed aboard the Defiant. Furthermore, O'Brien and the other top engineers in the rebellion were able to reverse engineer its internal workings and construct others.