Hagath was a Human arms dealer who operated in the 24th century, in partnership with Quark's cousin Gaila. Ruthless and calculating, Hagath hated to be "disappointed" and frequently had subordinates who failed him, such as Farrakk, killed.
Hagath had the foresight to provide the Bajoran Resistance with weapons during the Occupation of Bajor, which later allowed him to operate in the Bajor sector without interference. He knew that the Cardassians' overconfidence would ultimately cost them Bajor.
In 2373, Gaila suggested to Hagath that they employ Quark on Deep Space 9, as Quark's holosuites were ideal for the showcasing and sale of weaponry without any actual weapons passing through the station, circumventing Starfleet regulations. Quark, being heavily in debt at the time, accepted and for a time enjoyed substantial success.
Shortly after, Hagath took on a new client, the Regent of Palamar, who wanted biogenic weapons capable of killing 28 million people. Quark, suffering from a crisis of conscience, spoiled the deal by inviting the Regent's arch-enemy, General Nassuc, to Deep Space 9 at the same time. A firefight began when the two sides saw each other, alerting station security. Hagath and Gaila barely managed to escape the station alive, both with Nassuc's Palamarian Freedom Brigade purification squads behind them. (DS9: "Business as Usual")