Gaila was a Ferengi arms dealer who was eventually successful enough to buy his own moon. Odo once noted that he knew Gaila to be a more devious Ferengi than Quark, his cousin. (DS9 episode: "Civil Defense"; DS9 novelization: The Way of the Warrior)
In 2362, Gaila asked Quark to loan him the latinum it would take for him to start up his own munitions consortium. In return for the loan, Gaila promised that he would by Quark his own ship if he became successful in his venture. Despite eventually being rich enough to be able to by his own moon, Quark still did not receive his ship. Ten years later, Gaila finally sent Quark a Ferengi shuttle, which Quark designated Quark's Treasure. During the maiden voyage of the Quark's Treasure to Earth, Quark discovered that the shuttle had been sabotaged by Gaila in an attempt to kill him. (DS9 episode: "Little Green Men")
In 2373, Gaila and his business partner, Hagath, approached Quark to make use of his holosuites for use in their business endeavours. Though Gaila and Hagath had no qualms about selling weapons that would be used to kill millions of people, Quark began to have a crisis of conscience, particularly after learning the Regent of Palamar intended to buy biogenic weapons that would be used to kill millions of people.
Quark eventually double-crossed Gaila and Hagath by arranging for the Regent's enemy, General Nassuc to come to the station and "accidentally" run into them. Following the ensuing firefight, Gaila and Hagath fled the station with the Palamarian Freedom Brigade's purification squads in pursuit. (DS9 episode: "Business as Usual")
In 2374, Gaila was arrested on Thalos VI for vagrancy. Initially swearing revenge against Quark, his vengeance soon gave way to greed after learning about an offer to earn latinum by joining Quark's team to rescue his mother Ishka, who had been captured by the Dominion.
Gaila insisted that he was "a weapons dealer, not a soldier" and proved to be all too right as he jeopardized the mission more than once. First, he nearly allowed Keevan, the Vorta prisoner to be exchanged for Ishka, to escape when he fell asleep while guarding him. Later, after discovering that Quark intended to keep most of the reward money for himself, Gaila attempted to shoot him but shot and killed Keevan instead.
In 2376, Gaila was hired by the Petraw posing as the ancient Iconians to negotiation on their behalf to the Orion Syndicate, represented by Quark. Gaila used familiar ties with Quark to accuse him of being a Starfleet collaborator, staling while Nog worked to bring down the doorways. (DS9 novel: Demons of Air and Darkness)
Leter that year, Gaila was hired by Chek and Dav to bring former Grand Nagus Zek back to Ferenginar from Risa, to denounce his successor, Rom. Following this, Gaila approached Brunt, who had been disgraced in the scandal that followed, proposing a business partnership between the two. (DS9 - Worlds of Star Trek: Deep Space Nine novel: Ferenginar: Satisfaction is Not Guaranteed)
As partners, Gaila and Brunt first made deals to sell weapons to all three sides fighting on Kalanis Major. Afterward, they traveled to Risa for vacation, where Galia planted a man to tell Brunt about the Urwyzden system. They would then travel to this system and cause a war between the three planets of that system, all of whom they then sold weapons to. Eventually, Gaila came to believe Brunt and their pilot, Pel, were plotting against him. Gaila ordered his Breen guards to kill them, but both managed to escape. Brunt eventually returned and exposed Gaila's operation to the Urwyzden. Brunt then captured Gaila and turned him over to the Urwyzden, in order to make up for his part in the scheme. (ST novella: Reservoir Ferengi)
- DS9 - Gateways novel: Demons of Air and Darkness
- DS9 - Worlds of Star Trek: Deep Space Nine novel: Ferenginar: Satisfaction is Not Guaranteed