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For the Breen state of the same name in the mirror universe, see Breen Confederacy (mirror).

Breen Confederacy in known space (left of chart 1).

The Breen Confederacy was the interstellar state of the Breen species. (DS9 episode: "'Til Death Do Us Part") It was the fourth largest interstellar entity in known space. Only the United Federation of Planets, the Klingon Empire, and the Tholian Assembly were larger, the latter two being neighbors of the Breen. (ST reference: Star Charts)

The Breen Confederacy was headed by the Breen Domo. (ST - Destiny novel: Mere Mortals)

History and specifics

In 2375, under the leadership of Thot Gor, the Breen Confederacy allowed itself to be annexed by the Dominion, joining the Dominion War during that conflict's closing months. Forces from the Breen Confederacy launched an attack upon Earth, the capital planet of the United Federation of Planets, destroying much of Starfleet Headquarters, San Francisco, and other cities on the surface, killing thousands. (DS9 episodes: "Strange Bedfellows", "The Changing Face of Evil"; TNG - Tales of the Dominion War short story: "Eleven Hours Out")

While Breen forces initially led to several Dominion victories due to their energy-dampening weapon, the weapon was later countered, and the Breen later surrendered along with the rest of the Dominion in orbit of Cardassia Prime. The subsequent peace treaty re-established the Breen Confederacy and the Cardassian Union as independent states. (DS9 episode & novelization: What You Leave Behind)

The Breen Confederacy remained an object of concern for many in the Federation following the war. (DS9 novel: Avatar, Book One; TOS novel: Vulcan's Soul)

In 2381, the Breen attended a compulsory summit called by the Federation President in an effort to gain allies against the Borg Collective. (ST - Destiny novel: Mere Mortals)

A Breen.

The Confederacy would soon after join the Typhon Pact against the members of the Khitomer Accords. (ST - Destiny novel: A Singular Destiny)

In 2382 the Breen launched an intelligence mission against the United Federation of Planets at Utopia Planitia Fleet Yards. The Breen captured information related to the quantum slipstream drive in order to deliver working prototypes to the Typhon Pact members. They began work on a prototype vessel at the colony world of Salavat under tight scrutiny of the Romulan Star Empire and the Gorn Hegemony. The lead researcher of the project, Thot Keer, intentionally kept key research notes from the other powers in order to maintain the Breen's position within the Pact as a leading power. (ST - Typhon Pact novel: Zero Sum Game)


As was the case with most things surrounding the Breen, the nature and operation of their government was a mystery. Noted diplomatic observers had stated that they always dealt with an ever changing cast of lower ranking functionaries. These individuals were also quite reluctant in revealing their identities. The only determining factor in observations of Breen society was that their military officials made the high level decisions and there did not appear to be any civilian government.

Relations between the Federation and the Breen were described as tenuous at best by the year 2360. The territory of the Breen Confederacy resided near that of the Sheliak Corporate. This was a source of conflict between the two empires. (TNG novel: The Buried Age)

They also had some form of conflict with the Romulans with the Breen Confederacy managing to either emulate or steal cloaking technology from the Romulan Star Empire. Despite this hostility between the two, the Romulans never managed to decisively reach the Breen homeworld. (Decipher RPG module: Worlds)

Intelligence reports on Breen society and biology were consistently inconsistent and contradictory. It was only recently that a team of undercover operatives, after they made it inside Breen space,,and analysis by the "Jack Pack" revealed the Breen are in fact several different species working together. The suits employed by the Breen Confederacy were designed to provide every member of the Confederacy an equal chance to have success so that they were not biased against because of their species. Some of the more notable species include the human-like Silwaan; the Fenrisal, whose snouts required the distinctive shape of the Breen helmet; the bloodless Amoniri, who require refrigeration in their suits to prevent evaporation; and the Paclu, whose four-lobed brains defy telepathy.

It is important to note that there was an active dissident movement among the Breen colonies as of 2382, with many members wanting to seek political asylum within the United Federation of Planets. (ST - Typhon Pact novel: Zero Sum Game)

In 2409, Thot Trel used his influence to lead a pirate fleet into Deferi territory, the Orellius sector block. Trel's forces resorted to slavery and ransacked Defera Prime and became a menace for travel in the Deferi and Raveh sectors. (STO - Cold War missions: "Cold Call", "Out in the Cold")

Trel sought ancient weapons from the Preserver Archive on Lae'nas III but found his plans disappointed by the peaceful Progenitors. He was ultimately stopped by the Deferi's allies. However, some Breen dissidents joined the allied forces, retaining their refrigeration suits, inspired Medic Tran. (STO - Cold War mission: "Cold Storage")

Alternate timelines

In the mirror universe, the Breen Confederacy became a founding member of the Taurus Pact in 2377. (ST - Mirror Universe novel: Rise Like Lions)

In the Kelvin timeline, the Breen had been in conflict with the Tholians in the Origin sector for generations by the mid-23rd century. (ST video game: Fleet Command mission: "A Devil On Your Shoulder")

At one point, the Breen Confederacy planned an attack on Grazer V. The secretive Graviton Society of Starfleet engineered a coup that splintered the Confederacy before they could attack the Grazerite homeworld. Cadet Nyota Uhura learned of this development during her first year at Starfleet Academy in 2255. (TOS - Starfleet Academy novel: The Assassination Game)

By the 2260s, the Breen and the Tholians had left each other mostly alone. In that year, the Federation, Klingon Empire, Romulan Star Empire and other independent factions moved into the Origin sector, located in the Alpha Quadrant. Thot Trem contacted the Independent artificial intelligence Maia and warned her over the potential of reigning the conflict between the Confederacy and the Tholian Assembly if other factions moved into the Origin sector. The Breen were keen on protecting the sector's supply of isogen. The factions became party to the conflict between Breen and Tholians, led by Thot Trem and Ambassador and Commander Senise. (ST video game: Fleet Command mission: "A Devil On Your Shoulder")


species planet/system biology/suit accommodation admitted source
Amoniri Breen, Beta Epsilon-Venturi system liquid body, require refrigeration by 2372 ST - Typhon Pact novel: Plagues of Night
- Breen III, Breen system - by 2409 STO - Cold War mission: "Rescue Deferi Captives"
Dessev - - by 2383 ST - Typhon Pact novels: Zero Sum Game, Plagues of Night
Fenrisal - canine, with snout by 2372 ST - Typhon Pact novel: Zero Sum Game
Kalystarian - scaly and fish-faced by 2382 ST - Prey novel: The Hall of Heroes
Paclu Pacluro Prime strong, bulky, multi-lobed brains, multiple hearts by 2372 ST - Typhon Pact novel: Zero Sum Game
Silwaan - bronze-skinned humanoids founding member ST - Typhon Pact novel: Zero Sum Game
Vironat - gray-skinned humanoids with cleft extremities by 2384 ST - Typhon Pact novel: Plagues of Night


The territory of the Breen Confederacy resided near the Sheliak Corporate. The region of space out past Albireo was beyond the far border of Breen space, however, they had been establishing protectorates there for decades. This was part of a level of expansion spinward after their attempts at expanding anti-spinward were blocked by the Federation. This was a source of conflict between the two empires. (TNG novel: The Buried Age)

Map showing an angle of Romulan expansion into Alpha Quadrant.

The Romulan Star Empire holds some key territory in the Alpha Quadrant, including a frontier that borders the space of the Breen. (Last Unicorn RPG module: The Way of D'era: The Romulan Star Empire)



major states in the Alpha and Beta Quadrants
Khitomer Accords Cardassian UnionFerengi AllianceKlingon EmpireUnited Federation of Planets
Typhon Pact Breen ConfederacyGorn HegemonyHoly Order of the KinshayaRomulan Star EmpireTholian AssemblyTzenkethi Coalition
Khitomer Alliance Cardassian UnionDeferiDelta AllianceDominionFerengi AllianceKlingon EmpireLukari ConcordiumRomulan RepublicUnited Federation of PlanetsVoth Separatists
non-aligned states CortDaa'Vit ConfederacyDanteri EmpireFirst FederationGottar HegemonyGrigariHydran KingdomImperial Klingon StatesInterstellar ConcordiumJibetian ConfederacyKarg EmpireKentari UnionKzinti PatriarchyLyran Star EmpireMentosh AssemblyMetron ConsortiumNew Thallonian ProtectorateNyberrite AllianceOrion ColoniesPatriarchyRegnancy of the Carnelian ThroneSattar CollectiveSheliak CorporateShirn AllianceTalarian RepublicTarn EmpireTezwaTirrion AssemblyUbarrak PrimacyVenette ConventionVomnin Confederacy
defunct states Hiram AssemblyHradrian EmpireHusnock Star KingdomImperial Romulan StatePartnership of CivilizationsStellar Kingdom of CorillThallonian EmpireThelasian Trading ConfederacyZalkat Union
states unique to the mirror universe Galactic CommonwealthKlingon-Cardassian AllianceTerran EmpireTerran Republic
states from other alternate timelines AllianceErdenreichGalactic UnionIconian-Dominion AllianceInterstellar AxisInterstellar CoalitionInterstellar UnionKlingon-Andorian CompactVulcan-Andorian EmpireVulcan ProtectorateVulcan Star Empire
Interstellar nations in the Kelvin timeline
major powers Klingon EmpireRomulan Star EmpireUnited Federation of Planets
Alpha Quadrant states Borg Collective (Unimatrix 12) • Breen ConfederacyUnited Federation of Planets
Beta Quadrant states Augments factionFibonan RepublicGorn ArmadaGornar HegemonyKlingon EmpireMetron ConsortiumOrion SyndicateRomulan Star EmpireTeenaxi DelegationTholian AssemblyUnited Federation of Planets
Alpha or Beta Quadrant states Varkolak Assembly
Gamma Quadrant states Dominion
Delta Quadrant states Borg CollectiveDark Market Syndicate
mirror universes Klingon EmpireTerran Empire

External links