Zek was a male Ferengi, who had become Grand Nagus of the Ferengi Alliance by 2369. Zek was one of the most savvy and visionary Ferengi leaders, pioneering business ventures into the Gamma Quadrant and making the Ferengi Alliance the first Alpha Quadrant power that ever learned of the Dominion. In contrast to his cunning business practices, he also became known for his liberal attitudes towards the end of his reign including the expansion of female rights. Zek had one son, Krax.
In 2369, he suddenly announced his new successor, Quark (rather than his son Krax), and apparently died soon after. It was discovered that this was only a ploy to test his son's worthiness for the position. However, Krax did not succeed as expected, and Zek postponed his retirement. (DS9: "The Nagus") In 2370, Zek attempted to open negotiations with the Dominion, and although he opened contact with the Karemma and the Dosi for tulaberry wine, he was unable to contact the Dominion. (DS9: "The Nagus", "Rules of Acquisition")
Zek would later ask Quark to remind Sisko of his instrumental role in the events leading up to first contact with the Dominion, after his nephew Belongo, was detained by authorities on Aldebaran III. Sisko said he would look into the matter, but made no promises. (DS9: "Past Tense, Part I")
Later that year Zek came into possession of a Bajoran orb, and attempted to contact the Prophets to ask them to reveal the future to him for financial gain. Finding Zek's greed offensive, the Prophets returned him to Deep Space 9 after reverting him to a point in Ferengi evolution when the species was less profit-driven. With his mindset transformed, he believed the future was looking very bright, and recorded his thoughts in his personal log. He promptly created the Ferengi Benevolent Association to provide aid to poorer worlds, devised a revised version of the Rules of Acquisition that emphasized giving, and offered to give his orb to the Bajoran people for free. Though Rom speculated that he had gone insane, Quark quickly discovered that Zek had been altered by the Prophets, and convinced them to restore Zek to his former self. Zek then canceled all of his reforms. Zek was unaware, however, that Rom had embezzled money from the Benevolent Association while he was Senior Administrator. (DS9: "Prophet Motive")
In later years Zek began to experience a dramatic change in his policies. In 2373 he fell in love with Ishka, Quark's mother and a radical feminist who became the "power behind the throne." He eventually amended the Ferengi Bill of Opportunities to allow females the right to wear clothing. Few accepted this radical change at first, and Zek was ousted by Ferengi Commerce Authority liquidator Brunt. However, he was able to convince a few influential FCA commissioners that females represented an unexploited business opportunity, and Zek was reinstated. (DS9: "Ferengi Love Songs", "Profit and Lace")
Despite the Ferengi Alliance's official neutrality during the Dominion War, Zek maintained close relations with the Federation, and periodically requested status reports about the course of the war. In late-2374, Nog and Jake Sisko were on their way to Ferenginar, where Nog was to meet with Zek on behalf of the Federation, when their Runabout was ambushed by the Jem'Hadar. (DS9: "Valiant")
Shortly thereafter, Zek and Maihar'du (Zek's Hupyrian personal assistant) crossed over to the mirror universe hoping to make some profit. However, they were captured by the Alliance. Quark and Rom rescued them, by bringing Regent Worf a cloaking device. (DS9: "The Emperor's New Cloak") Later that year, Zek finally retired just after implementing radical new social welfare programs, appointing Ishka's son Rom as Grand Nagus, and passing to him the Grand Nagus' staff as a symbol of his new office. Zek and Ishka planned a subsequent stay on Risa. (DS9: "The Dogs of War")
Zek was an aficionado of Hupyrian beetle snuff. He was fairly liberal-minded for a Ferengi male, declaring his indifference towards Ferengi females who wore clothing inside the home, so long as they maintained the status quo by staying naked while in public.
|Grand Nagi of the Ferengi Alliance|
|Gint • Smeet • Zek (until 2375) • Quark (2369) • Brunt (2374, acting) • Rom (2375 onward)|
Zek was played by Wallace Shawn.
Shawn commented: "To be in that world and to be in that makeup really liberated me in a way that I never experienced before -- or since. I felt completely free, so it was a joyful experience. But it was physically very, very arduous, and I couldn't have done it on a regular basis. Once a year, which is what I did, was basically perfect for me. But to be trapped inside that head for at least 12 hours, not counting three hours to put the makeup on and an hour to take it off, was a little bit disturbing and uncomfortable and exhausting. And if you had to scratch your forehead, you couldn't". 
Shawn also commented that playing Zek: "was arduous, the hair and makeup – it took three hours! But it was thrilling. It was an amazing gift. It made acting very easy. If you looked in the mirror, you saw you looked very, very different. I had this anonymity; I was very free and could do what I wanted. It was fun". 
Zek was described in Star Trek 101 as: "Donald Trump, Alan Greenspan, and Scrooge McDuck all rolled into one diminutive wrinkled body".
Zek also appears in the novel The 34th Rule.