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Who Are the Breen?

Never turn your back on the mysterious yet aggressive humanoid species.

Stylized and filtered repeating images of Breen soldiers

The Breen are a reclusive and mysterious species whose government has long been considered a major power in the Alpha Quadrant.

Although details about them are often blended with hearsay, we have assembled a helpful briefing to get you up-to-speed on all things Breen.

Political Past

Severeal Breen soldiers stand together in 'The Changing Face of Evil'

"The Changing Face of Evil"

During the Klingon Second Empire, an entire Klingon fleet was dispatched to conquer the Breen homeworld, but no ships or soldiers ever returned from the mission. This fearsome reputation continued into the 2360s and 2370s, when the Breen were initially considered suspects in an apparent attack on the U.S.S. Vico (in "Hero Worship") and the Federation's Amargosa Observatory. The Breen also engaged in hostilities against the Cardassians, having destroyed the transport Ravinok and forced the survivors to mine dilithium.

The Dominion confined a Breen in Internment Camp 371 as part of its bid to infiltrate the Alpha Quadrant, but the prisoner was killed in an escape attempt. Given the Breen's clashes with so many other species, it's no surprise that the Romulans allegedly developed the saying, "Never turn your back on a Breen." Oddly enough, the Ferengi had managed to establish a rapport with the Breen and opened trade negotiations with them by 2373.


Close-up of a Breen helmet in 'The Changing Face of Evil'

"The Changing Face of Evil"

The Breen cover themselves in distinctive full-body suits, and their ever-present helmets mask their appearance from outsiders and process their speech through a metallic filter. Rumors of the Breen homeworld being a frozen wasteland lend credence to the theory that these suits are for environmental or refrigeration purposes, though Weyoun claimed that Breen has a comfortable climate.

Nevertheless, the Breen are often considered synonymous with all things cold by their interstellar neighbors. In the 24th Century, Data stated that the Breen are not detectable through empathic means, while Dr. Bashir noted that they do not have any blood.

The Breen Primarch removes his helmet to reveal his translucent green face in 'Mirrors'


According to Worf, no one had ever seen a Breen and lived to tell about it, which explains why the Federation did not immediately recognize the courier L'ak as a Breen in 3191. With the Breen finally unmasked, the species is shown to be capable of changing between two faces — a translucent and emerald-like flexible form, and a smooth, pale-green humanoid one. The latter shape takes focus and strength to hold, but unlike their more radiant appearance, the humanoid variant allows them to breathe the same atmosphere as most Federation species. The fluid that leaks out of a stab wound suffered by L'ak may indicate that Bashir's "no blood" observation is limited to the Breen's "other" face.


A Breen prisoner raises his phaser at a Jem'Hadar guard in 'By Inferno's Light'

"By Inferno's Light"

As one might expect when dealing with a populace who conceal their faces from other species, the Breen are incredibly secretive. In the 2370s, Worf asserts that the Breen are without honor and do not tolerate incursions into their space matches, while U.S.S. Voyager's Emergency Medical Hologram classifies them as a warlike species (as mentioned in "Elogium"). These comments reflect the Klingons' failed invasion of the Breen homeworld, but much more insight can be gained from the interaction between L'ak and his uncle, the Breen Primarch, as seen in "Mirrors."

The Primarch is displeased with L'ak's relationship with Moll, viewing the human as a "lesser being" and showcasing the Breen's intolerance toward non-Breen species. Great emphasis is placed on royal lines and family lineage, with the Primarch referring to L'ak's humanoid face as an insult to his heritage. In the Primarch's opinion, the Breen have evolved past that form as it makes them unfocused, inflexible, and weak. Ordering L'ak to redeem himself by killing Moll and the irrevocable nature of an Erigah — a Breen blood bounty — seem to reinforce the Federation's belief that the Breen are dangerous and cannot be trusted with the Progenitors' technology.

The Dominion War

Aboard a Jem'Hadar vessel, Weyoun marks a historic moment as the Breen Confederacy forms an alliance with the Dominion in 'Strange Bedfellows'

"Strange Bedfellows"

In 2375, Thot Gor allies the Breen Confederacy with the Dominion and quickly musters a fleet that succeeds in attacking Starfleet Headquarters on Earth. Equipped with organic-based ships, the Breen military helps the Dominion retake the Chin’toka system. The favoritism the Founder shows the Breen becomes a factor that pushes Damar into mounting a resistance against the Dominion. Breen energy-dampening weapons devastate enemy ships, though the Federation, Klingons, and Romulans soon devise a countermeasure which permits them to launch an offensive into Cardassian territory.

The Breen leaders witness the signing of the Treaty of Bajor by the Founders in 'What You Leave Behind'

"What You Leave Behind"

With their armada surrounded at Cardassia Prime, the Founder promises the Breen control of Romulus and Earth in a last-ditch effort to motivate them into fighting to the bitter end. The Breen leader vows to join the frontlines, but the Federation Alliance is bolstered by vessels from the Cardassian fleet. The Dominion and Breen Confederacy’s defeat proves inevitable, and the Founder eventually agrees to a complete surrender.

A 32nd Century Future

The Breen Primarch faces his nephew L'ak and reprimands him for consorting with lesser beings in 'Mirrors'


In the late 32nd Century, the Breen government is now known as the Breen Imperium. An independent entity that is separate from Osyraa's Emerald Chain, the Imperium runs its own space stations and trading hubs where couriers can sell their goods. While faction wars between rivals vying for control of Breen space have raged for years, continued infighting over a new leader has made the Imperium a growing threat and alarmed some Federation worlds.

When a time bug overtakes the U.S.S. Discovery-A, as seen in "Face the Strange," Captain Burnham witnesses a possible future in which the Breen secure the Progenitors' technology for themselves and launch a devastating attack on the Federation. By 3218, the Discovery is found to be adrift and Federation Headquarters has been obliterated. Once back in the year 3191, Burnham uses the glimpse into the future as evidence that the Breen Imperium must not be allowed to obtain the Progenitors' power.