Quark

Quark was a Ferengi male and the longtime owner and bartender of Quark's Bar, Grill, Embassy, Gaming House, and Holosuite Arcade, a wholly-owned subsidiary of Quark Enterprises, Inc., aboard the space station known as Terok Nor and, later, Starbase Deep Space 9.

In late 2376, his brother, Grand Nagus Rom, appointed Quark the Ambassador to Bajor, with Quark's bar serving as Ferengi Embassy. Quark also served a brief term as Grand Nagus of the Ferengi Alliance when it was believed that Grand Nagus Zek had died; he was removed from office and Zek restored when it was revealed that this was a ruse by Zek to test his son.

Early Life
As a youngster, Quark attended Hopawup Academy for Young Lobelings, and later Haryalevard Academy of Business Management. 

Quark left his home on Ferenginar in the year 2351, as soon as he reached his age of ascension.

At one point, Quark served as an apprentice to a Ferengi district sub-nagus, until a dalliance with the sub-nagus' sister (in which Quark forgot the 112th Rule of Acquisition) put Quark on the run from his former boss. 

Terok Nor
Afterwards, feeling the need to put some distance between himself and Ferenginar, Quark served on a Ferengi freighter as ship's cook under Daimon Gart. Quark served under Gart until 2360, when his vessel made a delivery to the Cardassian ore-processing center on the space station Terok Nor in the Bajoran system. Quark, seeing the opportunity for profit by selling food (at reduced cost) to the Bajoran laborers and providing a place for the Cardassian soldiers stationed there to relax and unwind when off-duty, decided to stay.

After bribing the station's commander, Gul Skrain Dukat, with a brick of gold-pressed latinum in order to be allowed to stay, Quark opened Quark's Bar, Grill, Gaming House and Holosuite Arcade aboard the station. The establishment quickly grew from a little gambling post in one of the storefronts, to the largest and most successful business on the station's promenade.

By 2363, Quark's brother Rom and nephew Nog had moved to the station after Rom's ex-father-in-law, Dav, swindled Rom out of everything he owned leaving him only his son and the clothes on his back. Quark gave them both jobs at the bar. 

In 2366, Quark, Rom and Nog were all exposed to a variation of the Double Helix virus, and were quarantined on the station until a cure was found. 

Deep Space 9
In early 2369, the Cardassians withdrew from the Bajor sector. The Bajoran Provisional Government requested relief aid from the United Federation of Planets, and they took over the running of the station, renaming it Deep Space Nine. Quark, fearing that business was about to dry up on the station, prepared to leave. The station's new Federation commander, Benjamin Sisko, 'negotiated' a deal with Quark that convinced him to stay, much to the amusement of Quark's nemesis, station Chief of security Odo. 

During the changeover from a Cardassian to Federation administration, Quark assumed that the Bajorans must have bribed the Federation in some way to get them to take control of Deep Space 9. He was deeply disgusted when he later learned that the Federation was there out of the goodness of their hearts. 

Quark was tricked by a Romulan officer, Katann, into testing a personal cloak device in the early 2370s. The device was only somewhat successful, and the Romulans gathered data on the side effects of the technology, pronouncing it unusable by members of their species due to dangerous radiation. Quark, in particular, was expected to be afflicted with severe diarrhea from his limited exposure. 

In 2371, Quark bought a glerint of Self-sealing stembolts from a Ferengi named Flem. Quark arranged for the transport of the bolts to Starbase 201, but the bolts didn't arrive as scheduled. (SS DS9 (Infinite Bureaucracy))

In 2372, when war was briefly declared between Ferenginar and Bajor, Quark and Rom were interned at the Gallitep labor camp, where they endured hideous treatment at the hands of the camp's insane warden, Colonel Mitra.

After their escape from Gallitep, Quark and Rom traveled to Ferenginar with Captain Sisko aboard the USS Defiant, and successfully aided him in defusing the tense situation between the two worlds. 

In 2376, after the Dominion War, Quark found himself developing an attraction to the stations new security chief Ro Laren. In April the station was attacked by a group of Jem'Hadar and Ro injured, falling from the stairs in his bar. Quark took the opportunity to play the hero and took her to the infirmary. He later sent Ro a bunch of Argelian flowers. 

Later that year Quark represented the Orion Syndicate in negotiations with the race claiming to be the ancient Iconians during the Gateways Crisis. Unbeknownst to the Orions, Quark was actually working with Bajoran security officer, Ro Laren, who succeeded in taking down the organization of the Orion criminal, Malic. Quark and Ro freed an Orion slave girl named Treir from servitude to Malic and she accepted Quark's offer of a job as a dabo girl. 

Ambassador Quark
In September of 2376, as Bajor prepared to join the United Federation of Planets, Quark was once again preparing to leave, as the Federation's economy was nominally money-less, leaving Quark with few options to obtain profit in the Bajoran system.

Quark had been pursuing a romantic relationship with Ro Laren, who also didn't feel as if she had any future in the Federation, and hoped that she would join him in whatever future endeavors came his way. This ceased to be an option when Starfleet took Ro back despite her checkered past.

Luckily for Quark, his brother Rom was the new Grand Nagus of the Ferengi Alliance. Rom opened diplomatic relations with Bajoran First Minister Asarem, and appointed Quark to be Ferenginar's Ambassador to Bajor, with his bar being sovereign Ferengi territory, allowing him to continue his business. 

He returned to Ferenginar soon after to attend the birth of his niece, Bena, daughter of Rom and his Bajoran wife, Leeta. While he was there, he helped Rom fight off an attempt to have him removed from his Nagus-hood by Ferengi congressman, former FCA agent, Brunt. 

Quark was still aboard Deep Space 9 in 2382 and was still an ambassador. He was in a romantic relationship with Captain Ro. 

When the station was destroyed in 2383, he managed to successfully evacuate. Later on during the construction of the new Deep Space 9, Quark indicated that he had every intent of reopening his bar, which also stood as the Ferengi Embassy to Bajor. Nog told construction teams to add in an extra holosuite or two for Quark. 

After the original Quark's was lost in the Destruction of Deep Space 9 in 2383, Quark relocated his business to Aljuli on Bajor, near to Bajoran Space Central. Once construction of the new Deep Space 9 was complete, Quark opened a new establishment there, and left the profitable Aljuli under former dabo girl Treir's management. The new Quark's opened for business a few days before the starbase was officially opened. 

In 2385, Quark and Shmenge traveled to Wrigley's Pleasure Planet to speak to Ardon Broht about a new sequel to Vulcan Love Slave. 

Alternate realities
In an alternate reality, Quark likewise ran a bar on Deep Space 9. In 2371, Federation and Dominion delegations met on DS9 to negotiate a treaty in response to the Dominion's peace overtures in 2371. However, during the talks, Odo was murdered with a phaser. Consequently, the negotiations broke down and the Dominion launched an attack on DS9. Although the Federation forces were eventually able to push the Jem'Hadar back through the Bajoran wormhole.

While posing as his murdered counterpart, the Odo of the primary universe told Quark that not even death could keep him from getting the goods on him. When Curzon Dax expressed doubt that Quark could have been complicity in his counterpart's murder, Odo acknowledged that this was probably true but that he enjoyed giving Quark the shock of his "misspent life" in any reality. Odo later determined that the alternate Major Kira Nerys was responsible for killing the other Odo as she feared the consequences for Bajor if the Federation and Bajor were to form an alliance.