||This Star Trek-related article describes a work or element of fiction in a primarily in-universe style. (October 2009)|
Ikat'ika, a Jem'Hadar soldier in 2373
|Founded||Genetically engineered by the Founders|
|Base of operations||Gamma Quadrant|
The Jem'Hadar are fictional characters in the TV series Star Trek: Deep Space Nine. They are the shock troops of the powerful Dominion located in the Gamma Quadrant. Genetically engineered for strength and resolve, they are also short-lived and believe that "victory is life." They are bred to perceive the Founders, enigmatic shape-shifters who rule the massive Dominion, as gods and are incapable of harming them. The Jem'Hadar's numbers are unknown, but they are produced by the thousands as needed.
Conceived as "more than just another fearsome alien", the Deep Space Nine makeup department searched for concepts depicting "toughness and resiliency" in the design of the Jem'Hadar. The final design was based on a rhinoceros, with some added ceratopian traits. Originally designed on the premise that they were all clones, the first Jem'Hadar seen onscreen were all made to look identical to one another, though as they became more deeply woven into the storylines, each Jem'Hadar was given a distinctive look.
Biology and control 
It is unknown if a base species was genetically altered into the Jem'Hadar (as is the case with their Vorta overseers) or whether they were completely designed by the Founders.
Jem'Hadar are born in "birthing pods." As there is no individual reproduction, the Jem'Hadar are all male. After emerging from the birthing pod, the Jem'Hadar grows rapidly and is a battle-ready young adult in three days. They are bred without the need to eat, sleep, rest, relax or to pursue recreation, though during their growth periods they must consume massive quantities of food. The Jem'Hadar are also bred for proficiency in hand-to-hand combat, having an extremely tough and strong physique, with leathery, lizard-like skin. Jem'Hadar have a personal cloaking capability they call "shrouding". According to Deep Space Nine episode "The Abandoned", this ability is a part of their integrated biology - in the DS9 episodes "Hippocratic Oath" and "Rocks and Shoals", Jem'Hadar who are suffering from Ketracel White withdrawal lose their ability to shroud.
The only nourishment they require comes in the form of the hormonal enzyme Ketracel White (or simply "[the] white"). Without this drug, Jem'Hadar go into severe withdrawal, resulting in loss of cognitive and motor functions. They will lose their shrouding ability and regress into a highly aggressive stage, not discriminating in whom or what they attack, including their Vorta superiors and peers. Lack of white will eventually kill a Jem'Hadar. The Founders use the Vorta to supply the Jem'Hadar with the white. It is administered through cylinders that fit into a system near a Jem'Hadar's collar, which is then fed directly into the Jem'Hadar via a tube running into the carotid artery. Distributing the white is a formal ceremony: the Vorta says "First [name of Jem'Hadar first], can you vouch for the loyalty of your men?". The First replies "We pledge our loyalty to the Founders, from now until death". Unlocking the repository, the Vorta says "Then accept this gift from the Founders. May it keep you strong", handing out the vials of white. However, according to DS9 episode "One Little Ship", in the case of "Alphas" (Jem'Hadar bred in the Alpha Quadrant and designed specifically for combat there), the Founders decided to dismiss this ritual.
Early in the Federation-Dominion war, unable to get backup from the Gamma Quadrant, the Founders in the Alpha Quadrant engineered the "Alpha" Jem'Hadar. The Alphas have a variation in the facial and head structures and more flippant attitude toward doctrine and procedure; the latter created animosity between the two breeds. It was intended to show fuming hatred between the "Alphas" and "Gammas", culminating in all-out violence; however, this was only explored in one episode.
The Klingons believe that the Jem'Hadar are no more than honorless machines. However, the Jem'Hadar are a species of varied characters, although these variations are across a more narrow spectrum than is typical in the Star Trek universe. Jem'Hadar have a high mortality rate; few live to be fifteen and none are known to have lived to be thirty. A Jem'Hadar who reaches twenty years of age is considered an "honored elder."
The Jem'Hadar are typically extremely loyal to their overseers. In "Rocks and Shoals", a group of Starfleet officers led by Captain Sisko are stranded on an uninhabited planet along with a group of Jem'Hadar and their Vorta, Keevan. Keevan is injured and needs medical attention to survive, so he decides to surrender himself. He informs Sisko how he will order his troops to attack so that Sisko can ambush and kill them. Even though the Jem'Hadar leader suspects Keevan's plan, so strong is their loyalty that the Jem'Hadar willingly walk into the trap as ordered. Earlier, in "The Ship", a group of Jem'Hadar commit suicide because they fail to save the life of a Founder.
However, other Jem'Hadar have been less devoted. "To the Death" featured a group that gained control of an Iconian gateway and plan to use it to rebel against the Founders. Their leader expected this group to pick up considerable support, to the point where the Jem'Hadar as a whole would be able to seize control of the Dominion and liberate themselves from the Founders. Even after these had been defeated, however, the loyal Jem'Hadar First murdered their Vorta for questioning their loyalty.
The Jem'Hadar command structure is fairly straightforward. A particular unit's leader is called a "first", the second in command is the "second", and so on down the chain of command. In "To the Death", the ranking Jem'Hadar gave the following battle dirge to his assembled troops:
- I am First [name of Jem'Hadar First], and I am dead.
- As of this moment, we are all dead.
- We go into battle to reclaim our lives.
- This we do gladly, for we are Jem'Hadar.
- Remember: Victory is Life!
- Assembled Jem'Hadar: [chanting shout]
- Victory is Life! Victory is Life! Victory is Life!...
When someone questions an order of a superior Jem'Hadar, or even of the Vorta, the superior reminds them to the "order of things", by this phrase:
- Obedience brings victory.
For which the answer is:
- Victory is life.
Weapons and equipment 
Jem'Hadar use phased polaron weaponry, both for handheld and ship-mounted weaponry. Apart from their sheer destructive force, Jem'Hadar weapon beams emit a pulse that prevents coagulation in impacted biological tissue; even a glancing wound will cause unstoppable bleeding and death if untreated. In most other regards, Jem'Hadar small arms appear comparable to those used by Starfleet, Klingons and Cardassians. In addition, ship-mounted phased polaron beams were able to penetrate the shields of Federation, Cardassian, and Romulan ships. By a stroke of luck, in 2373 Starfleet was able to capture an intact Jem'Hadar fighter and reverse engineer the weapons, developing an effective defense. This helped prevent the Dominion from achieving victory early in the Dominion War.
The Jem'Hadar also use edged weapons, including a small, curved blade designed to be held in one hand (and often used, rather oddly, as a bayonet on their energy carbines), and a larger sword-like weapon usually held with two hands. In early encounters, Jem'Hadar can walk through Starfleet forcefields. According to startrek.com, this ability is derived from energy-absorbing pads built into their uniforms. However, the same source also indicates their shrouding ability to be derived from technology, despite the fact that the episode "Rocks and Shoals" explicitly established the ability to be biological.
The Jem'Hadar boast starships of unique design. These include relatively small, beetle-like attack ships  that are comparable in size to the USS Defiant, and larger battleships  first seen in "Ties of Blood and Water".
Their ships' bridges contain no central viewer, with only the First and their Vorta permitted to use a head-mounted display head-set to see outside the ship. There are no seats for the crew; everyone must stand (in the episode "One Little Ship", the First orders the chairs removed from Defiant's bridge). The beetle-like attack ships are sufficiently well-built to survive plummeting uncontrolled into a planet's surface and subsequently being repaired and flown again (DS9: "The Ship").
Involvement in the Dominion War 
Hostilities between the powers of the Alpha Quadrant and the Dominion began with the Jem'Hadar's kidnapping of Benjamin Sisko and Quark. Simultaneously, the Jem'Hadar destroyed several Alpha Quadrant colonies and ships in the Gamma Quadrant. The Jem'Hadar kamikaze attack destroyed the USS Odyssey while the damaged starship was retreating after a mission to rescue Sisko and Quark. (DS9: "The Jem'Hadar")
The Jem'Hadar are the spearhead for the Dominion's invasion of and advances through the Alpha Quadrant. Although the Dominion allies itself with the Cardassians and the Breen, the Jem'Hadar remain at the forefront of the Dominion's forces. A Dominion reinforcement fleet would have spelled doom for the Alpha Quadrant defenders had the wormhole aliens not intervened and caused the fleet to vanish (DS9: "Sacrifice of Angels"). Even without these reinforcements, the war persists — and the Jem'Hadar continue to fight — for almost two more years.
After heavy losses, the Dominion War ends in 2375, and the Jem'Hadar withdraw to the Gamma Quadrant.
- Michael Westmore, Alan Sims, Bradley M. Look, William J. Birnes (2000). Star Trek: Aliens and Artifacts. p. 208. ISBN 0-671-04299-8.