The Jem'Hadar have a reptilian appearance, with bluish-grey skin and vestigial horns. Due to extensive genetic engineering, they do not breed, eat, drink or sleep; they subsist entirely on Ketracel-white. Jem'Hadar are born in hatcheries and kept in stasis until they are deployed. Their development is extremely rapid, going from birth to adulthood in three days. Their average life expectancy is less than 20 years; no Jem'Hadar has lived to see 30.
Jem'Hadar possess a rudimentary cloaking ability known as a "shroud", which is capable of visually blending a Jem'Hadar in with his surroundings.
- "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."
- -- Jem'Hadar ritual pre-battle address
The Jem'Hadar are bred and conditioned to be what the Dominion considers "perfect soldiers". They are fanatically devoted to the Founders, whom they revere as gods; failure to adequately protect a Founder is seen as sufficient reason to commit suicide. Jem'Hadar have a rudimentary rank system based on seniority, although all Jem'Hadar are subordinate to the Vorta. Their only purpose in life is military service; because of this, they feel no need for entertainment or personal relations. Jem'Hadar often employ "human wave" attacks against enemy positions.