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; was an aficionado of Hupyrian beetle snuff; and, was also taught how to go into a Dolbargy sleeping trance, by his servant Maihar'du. By 2369, Zek was already considered to be in "his advanced years." (DS9: "The Nagus") Following a physical later given by Doctor Julian Bashir, in 2371, Zek was said to be, "for a Ferengi [his] age" to be "in excellent health", except for "some vascular damage to [his] mucus membranes" from his beetle snuff use. (DS9: "Prophet Motive")
Expansion into the Gamma Quadrant
In 2369, Zek arrived at Deep Space 9 where he sought out Quark, the proprietor of Quark's Bar, located on the station's Promenade. Although the reason for his presence was not immediately revealed, he wished to use Quark's holosuites, having heard that some of Quark's programs were "quite alluring." When Quark gave Zek a selection of his top five favorites, he decided to sample them all, after which Quark volunteered Rom's quarters for the Nagus to rest in. Following his rest, he told Quark to invite him to dinner, where Quark offered tube grubs, that Zek found to be "chilled to perfection."
As Zek slowly revealed his intentions, he complimented Quark on his "stroke of brilliance" to establish his bar so close to the Bajoran wormhole. He then asked Quark for the favor to using his bar and services as host "for an important conference" he had planned to hold the following day, to discuss "the future" of "Ferengi business interests", namely "the Gamma Quadrant." As the meeting started, Zek requested that Quark stay.
Following concerns that "it is becoming more and more difficult to find truly lucrative business opportunities here in the Alpha Quadrant [...] because no matter where we go, our reputation precedes us." Zek unveiled his plan, "thanks to the discovery of the wormhole," which opened access to "millions of new worlds at our very doorstep," meaning that "the potential for Ferengi business expansion [was going to be] staggering." As the conference attendees expressed their support for the Nagus' plan, he declined the offer, stating, "I'm old. The fire dims. I'm just not as greedy as I used to be," before suddenly announced that he wished to retire, and going naming his new successor – Quark.
Following his retirement, Zek began making considerations where he would go next Risa or Balosnee VI, this while Quark, overwhelmed with his new responsibilities as Grand Nagus, sought Zek's counsel. As Zek explained the basics of his old role, he apparently died mid-thought, from an apparent "massive infection of the tympanic membrane. A chronic condition." His body was, soon after, and apparently, "automatically vacuum-desiccated and sold as a prized collectible."
As attempts were underway to assassinate Quark by Rom and Krax, Zek revealed himself and it was soon discovered that his death was only a ploy to test his son's worthiness for the position. However, Krax did not succeed as expected, Quark abdicated the position back to Zek, and Zek postponed his retirement, hoping only "long enough to establish a Ferengi presence in the Gamma Quadrant." Zek then promised Quark if "any good deals" that were right for Quark opened up. (DS9: "The Nagus")
Later that year, when Odo's imagination became reality and a duplicate of Quark was kept in a holding cell, the false Ferengi demanded to talk to the Nagus over subspace. (DS9: "If Wishes Were Horses")
In 2370, Zek attempted to open negotiations with the Dominion, and although he opened contact with the Dosi for tulaberry wine, eventually leading him to more important members of the Dominion, the Karemma. (DS9: "Rules of Acquisition")
In 2371, Zek appointed Quark as his representative to accompany the USS Defiant on its mission to make contact with the Founders of the Dominion, through Benjamin Sisko. (DS9: "The Search, Part I") 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 domestic interests
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 cancelled 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 his later years, Zek began to experience a dramatic change in his policies. 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. 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")
The Dominion War and expansion into the mirror universe
In early 2374, Zek offered to buy Rom's freedom from the Dominion. (DS9: "Favor the Bold") Later, when the transport ship Ishka was aboard was captured by Dominion forces while returning from a trip to Vulcan, Zek requested that Quark rescue her, offering an incentive payment of fifty bars of gold-pressed latinum. (DS9: "The Magnificent Ferengi")
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")
Later that year, Zek and Maihar'du 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")
|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.
The novel The Buried Age establishes that Zek was responsible for creating propaganda over the supposedly threatening nature of the Ferengi in early I AM ERROR because the Ferengi, after hearing early reports about the Federation and their moneyless economy, decided that the Federation might well be insane if they truly did not seek profit. Zek also threw funding into a large military buildup in order to preserve their appearance as a dangerous race and in order to defend themselves against the Federation, should it prove necessary.