The Grand Nagus is the
Ferengi financial leader in the
Star Trek universe. Responsible for providing leadership and guidance in the realms of finance, investments, trade territories, and other such commercial opportunities, the male who holds the office of Grand Nagus controls the entire
Ferengi empire. Holders of the position live in the traditional Nagal residence on
Ferenginar near the
Tower of Commerce in the
Sacred Marketplace where they hold daily meetings to discuss new profit initiatives and economic forecasts in the
Chamber of Opportunity. Tradition dictates that the Nagus carries a wooden cane with a golden bust of a
Ferengi head positioned at the top; all who see the Nagus must kiss the golden figure as a sign of respect. Upon the death of a Nagus the
Ferengi Futures Market is quick to acquire the body and have it
vacuum desiccated in order to divide it into collectable chunks that are sold for high prices.
There have been a number of Grand Nagi over the centuries, but only a few were ever explicitly mentioned onscreen. The first Grand Nagus was Gint, the ancient entrepreneur who wrote the first Ferengi Rules of Acquisition and united the waring Commerce Zones into a single unifed society. Ferengi believe that when they die they go to the Divine Treasury where Gint awaits them. Following his reign are the reigns of other Nagi including Yost, Drik, Frek, Brolok, and Oblat. Then came the first Nagus to be assassinated, Smeet; his death came as a result of the revolt following the disastrous futures market crash. During this volatile period DaiMon Vurp seized power, turning the Ferengi culture into a military dictatorship for a brief period. After the death of Vurp came a return to the traditional Nagal reign with the eras of Nagi such as Untz and Twim (Twim being the Nagus who outlawed time travel in the name of profit).
One of the most popular and controversial of all Grand Nagi was Zek, the person responsible for opening up trade with the then-mysterious Dominion in the Gamma Quadrant in 2369. Near the end of his time in office Zek fell in love with Ishka, mother of Deep Space Nine bartender Quark (himself a former Nagus for a very brief period), and she began to fill his head with ideas of female empowerment and equal rights. Zek instituted a number of reforms on Ferenginar to give females equal footing with the males, and as such they were allowed to wear clothing and acquire profits of their own. Many Ferengi had their eyes on Zek's job (including his own son Krax and Ferengi Commerce Authority Liquidator Brunt), but when he stepped down in 2375 to retire to Risa with Ishka he named Quark's brother Rom as his successor to lead a new era in Ferengi history that included income taxes, social reforms, and government programs, thus turning the society into somewhat of a democratic republic.
References:
http://www.powernet.net/~jcrafton/ranks.html#nagusgrand
http://en.wikipedia.org/wiki/Ferengi
http://www.startrek.com/startrek/view/library/places/article/69528.html
http://www.startrek.com/startrek/view/series/DS9/character/1112445.html