Played by: Wallace Shawn
Full name: Zek
Position/occupation: Business leader/kingpin
Rank/title: Grand Nagus
Birthplace or childhood home: Ferenginar (presumably)
Child: Krax (son)
Other family: Belongo (nephew)
Love interest(s): Ishka
Hobbies/likes/interests: Hupyrian beetle snuff
Zek first came to DS9 with his son Krax and his servant Maihar'du in tow, in "The Nagus", in which he named Quark his successor and then faked his death, which turned out to be a test for Krax -- who failed miserably, in Zek's view. Zek returned in "Rules of Acquisition", to have Quark negotiate a deal with the Dosi, for 10,000 vats of tulaberry wine; this was part of a plan to make contact with members of the Dominion.
A year later, in "Prophet Motive", Zek went into the wormhole with an Orb he had acquired, and consulted the Prophets, in hopes of gaining advance knowledge of economic changes. Instead, he was changed by them into an earlier version of his people: a kindly philanthropist. Quark eventually convinced them, however, to change Zek back to his greedy self.
At some point, Zek met Ishka after corresponding with her (which started when she gave him tips that helped him win a Tongo championship). In "Ferengi Love Songs", Quark discovered that they were involved. In fact, Ishka was also secretly aiding Zek due to his failing memory. Though they broke up briefly due to Quark's machinations on Brunt's behalf, Zek survived Brunt's attempt to expose him, and made Ishka his presumably unofficial advisor. He planned to seek Vulcan medical aid for his memory loss.
Due to Ishka's influence, Zek (who was previously as sexist as any male Ferengi) instituted a series of reforms giving equal rights to females, including the right to wear clothing. This upset the status quo so much that Zek was deposed. In "Profit and Lace", Zek came to DS9 with Ishka, planning to present her to the FCA Commissioners to convince them to restore him. Despite several snags (forcing Quark to pose as a female), Nilva agreed to use his influence on Zek's behalf; and Zek was eventually reinstated.
After finding information on Rom's engineeering PADD on how to cross over to the mirror universe, Zek couldn't resist the opportunity, and went there in hopes of expanding Ferengi business. Instead, however, Zek was taken prisoner by the Alliance, and was held hostage in exchange for a cloaking device. He was eventually rescued along with Quark, Rom, and Maihar'du when Regent Worf was captured ("The Emperor's New Cloak").
In "The Dogs of War", Zek sent a static-garbled message saying that he planned to retire and move to Risa with Ishka, and that he was coming to DS9 to name his successor. Quark thought it would be him; however, when Zek did arrive, it turned out that he had meant Rom.
Appearances: "The Nagus", "Rules of Acquisition", "Prophet Motive", "Ferengi Love Songs", "Profit and Lace", "The Emperor's New Cloak", "The Dogs of War"