Ancient civilization of shape-shifters, the architects of the Dominion in the Gamma Quadrant. Long ago, the Founders explored the galaxy, but found themselves to be feared, hunted and killed by the solids, their term for non-shape-shifters. Out of self-defense, the Founders retreated to the a planet in the Omarion Nebula. From this location, the Founders established the Dominion, through which they controlled hundreds of planets throughout the Gamma Quadrant, imposing order through ruthless violence and fear. Although isolated, the Founders did not lose their curiosity about the universe. They sent a hundred infant members of their species across the galaxy, implanting in each a powerful desire to return home, so that the Founders could learn about distant places. Deep Space 9 security chief Odo was one of these infants. The Founders had a strong family link to each member of their species, and it has been said that no shape-shifter has ever killed another. Another of these changeling infants ended up on Deep Space 9 in 2373. Odo began to rear the infant, until it died of radiation that it had been exposed to while in space. The Founders' ability to assume the shape of an object is so complete that a Founder in the guise of an individual of another species is virtually undetectable, even with sophisticated scanning equipment. Should, however, a piece of a Founder's body be separated from the main body mass, the separated piece reverts to its normal gelatinous state. Starfleet phasers set to a force of 3.5 were sufficient to force a Founder to revert to a gelatinous state. Founders also revert to a gelatinous state upon death. The Founders used a warrior species called the Jem'Hadar to force compliance of the various members of the Dominion. The Founders maintained control of the powerful Jem'Hadar through the use of genetic engineering, altering Jem'Hadar physiology to be dependent on ketracel-white (also known simply as "white," an isogenic enzyme), a drug that only the Founders could supply, through their agents, the Vorta. Some Vorta agents suspected that even this extreme measure may not have been sufficient to control the Jem'Hadar's powerfully violent tendencies. Most Jem'Hadar spent their entire lives without meeting a Founder. To them, the Founders were thought of as myths or even gods. On stardate 50049.3, a Founder was mortally injured when a Jem'Hadar ship crash-landed on planet Torga IV. The Jem'Hadar that came to rescue him, having failed in their mission, committed suicide for letting the Founder die. In 2371, the Founders learned of Enabran Tain's scheme to attack the Dominion. They took advantage of the situation, staging an ambush in the Omarion Nebula that virtually annihilated the armed forces of the Obsidian Order and the Tal Shiar. The incident substantially reduced the ability of the Alpha Quadrant powers to resist a potential Dominion invasion. The Founders also tried to initiate a war between the Federation and the Tzenkethi, hoping to make the Alpha Quadrant more susceptible to Dominion attacks. Sometime before 2373, the Founders replaced Klingon General Martok, in hopes the Dominion could gain control over the Klingon Empire. In order to reduce suspicions on the ersatz Martok, the Founders, through the Great Link, caused Odo to believe that Gowron, not Martok, had been replaced by a changeling.
In 2373, the Founders entered into an alliance with the Cardassian Union, giving the Dominion a significant foothold in the Alpha Quadrant. The agreement was a source of great concern to many Alpha Quadrant powers, and resulted in the reinstatement of the Khitomer Accords. Founders' homeworld Sunless Class-M planet located somewhere in the Omarion Nebula in the Gamma Quadrant. The planet was the home of the reclusive civilization of shape-shifters known as the Founders and the central planet of the Dominion. In 2371, the Tal Shiar and Obsidian Order launched a massive attack against the Founders' homeworld, bombarding the planet's surface with a fleet of 20 starships. Neither attacker realized that the Founders had evacuated the planet, or that they had a fleet of 150 Jem'Hadar ships waiting to destroy the invaders.