Breen

The Breen were a spacefaring humanoid species native to the planet in the Alpha Quadrant. Notoriously reclusive and warlike, the Breen were a formidable power in their region of the galaxy. They almost always wore refrigeration suits that entirely concealed their bodies.
== History ==
The Klingons were among the first to discover that the Breen did not tolerate incursions into their space. During the Klingon Second Empire, Chancellor Mow'ga ordered an entire fleet of Klingon warships to invade and conquer the Breen homeworld. The fleet never returned and was never heard from again. ()
The Romulans' contact with the Breen led to their coining a saying: "Never turn your back on a Breen." ()
===24th century===
Even by the 24th century, much was still unknown about the Breen and their government, known as the Breen Confederacy. () The Federation had limited knowledge of the Breen, however, and was aware of Breen outposts located in Sector 97 in 2368. That same year, Starfleet feared the Breen might have attacked the science vessel there. ()
Breen privateers during the 24th century often conducted indiscriminate raids against other Alpha Quadrant species. This included the Breen attack and capture of a Cardassian Central Command vessel, the Ravinok, in 2366. The survivors of that attack were used for slave labor in Breen-operated dilithium mines on Dozaria. ()
In 2370, the Breen participated in a palio held at Federation space station Deep Space 3, during which the Ferengi attempted to bribe a Breen pilot into deliberately losing the race. ()
In 2371, evidence seemed to briefly indicate that the Breen may have attacked another Federation space station, the Amargosa observatory, though the true aggressors were, moments later, determined to have been Romulans. () Nevertheless, by about this point, the Breen were considered one of the most warlike species known to the Federation. ()
In 2372, the Breen captors on Dozaria were located by Kira Nerys and Gul Dukat. Dukat stated that he didn't approve of what the Breen were doing, by employing the survivors of the Ravinok as slaves but did "admire their ingenuity." The Breen guards were ambushed by him and Kira, so that they could free one of the Breen's prisoners: Dukat's daughter, Tora Ziyal. () Later that year, Breen privateers raided the Bajoran colony of Free Haven; they were, however, successfully driven away by the . ()
By 2373, the Cardassian Union maintained an embassy on the Breen homeworld. () The same year, Breen settlements on Portas V, near the Demilitarized Zone, dealt with the Maquis, supplying them with cold storage units. ()
Whereas a Breen individual was held captive by the Dominion at Internment Camp 371 in 2373 (before killing a couple of Jem'Hadar guards there and, in retaliation, being shot to death in that year), other species like the Ferengi had developed closer ties with the Breen by the late 24th century, as both species conducted trade negotiations in 2373. () Once, in 2374, Ferengi engineer Rom referred to the Breen as one of the top three toughest mercenary species that he and his brother, Quark, could find (the others being Klingons and Nausicaans). Rom suggested including the Breen in a commando team which would be sent to rescue his and Quark's mother, Ishka, who was being held prisoner by the Dominion, but Quark declined the Breen's involvement, opting for the rescue operation to be attempted by Ferengi only. Ishka's captor, Vorta clone Yelgrun, considered Breen annoying, though not as much as Ferengi. ()
It was noted by Ezri Dax in 2375, when she and Worf were captured by the Breen on the planet Goralis III, that they were a long way from Breen space. () The Breen interrogated Worf and Dax, but the information which the pair consequently provided was somewhat confusing. () In Worf's opinion, the Breen were not only dangerous but also had no honor. ()
In 2380, Lieutenant Barbara Brinson suspected Ensign Beckett Mariner of being a Breen infiltrator. ()
==== Alliance with the Dominion ====
:Main article: Breen-Dominion Alliance
Meanwhile, Breen representative Thot Gor had been extensively conversing over subspace with the Female Changeling, the leader of the Dominion, in discussions that she found to be particularly productive. () The Breen were of no personal interest to her other than the military advantage they could provide against the Federation Alliance in the Dominion War, in which the Female Changeling was determined to lead the Dominion to victory. () In 2375, the Breen moved from a policy of low-level hostilities toward most other major powers to one of open warfare when they allied themselves with the Dominion as reinforcements. () To mark the historic moment when the two parties first met in person, the Breen presented Worf and Ezri Dax as gifts to the Dominion. ()
According to the terms of alliance, the Breen Confederacy received several planets in the Cardassian Union as compensation for joining the war. Despite being welcomed by the Female Changeling and Vorta leader Weyoun, the Breen were mistrusted by the leader of the Cardassian Union, Legate Damar, who was frustrated by the details of their treaty with the Dominion. For instance, the Breen were thereafter allowed unlimited access to the Dominion's database, whereas Damar was annoyed at them being permitted to use it at all. His frustration over how the Breen were being received led Damar to begin a Cardassian rebellion against the Dominion and enable Ezri Dax and Worf to escape back to Federation space. () Even for the Cardassian rebels, the addition of the Breen made the Dominion more formidable than ever. ()
Shortly after joining with the Dominion, the Breen attacked Earth, assaulting Starfleet Headquarters and destroying the nearby Golden Gate Bridge. Most of the Breen attack force was destroyed by Starfleet, though the majority of the damage on Earth had been done by that time.
The Breen were so secretive that the only thing Starfleet knew about them, up to then, was that they were a race of warriors, an aspect of the Breen which the Klingons learned in light of their attack on Earth, as not even the Klingons had ever attempted such a strike. Even Weyoun and Damar considered the Breen to be "full of surprises," albeit for different reasons. ()
A short time later, the Breen assisted Dominion forces in breaking the lines at Chin'toka, launching a counteroffensive against the Federation Alliance there and breaking through in two places. To Rom's son, Starfleet Ensign Nog, the Breen now seemed unstoppable, though Worf refuted this opinion, believing that every foe could somehow be overcome. A major battle which followed, known as the Second Battle of Chin'toka, was won by the Dominion thanks to a unique Breen device, a kind of energy-dampening weapon which could completely drain all the main power systems of a starship. Those vessels which were destroyed by the Breen weapon during the battle included the USS Defiant. () In fact, the only ship immune to the weapon was a Klingon Bird-of-Prey, the , which serendipitously survived thanks to an adjustment the chief engineer had made to the ship's tritium intermix in the warp core. () Under orders from the Female Changeling, the Breen allowed escape pods to carry Federation survivors to safety (believing they would sow fear in the enemy ranks after what they had witnessed), and the Breen were thanked for the decisive part they had served in the battle. () Both this defeat and the Breen's devastating assault on Earth dealt a huge blow to the Federation Alliance's morale. () The Breen were also being used to defend numerous Dominion facilities. ()
Breen engineers were assigned to begin retrofitting Dominion ships with the energy-dampening weapon. The engineers were instructed to accelerate the installation program, an order that had been sent from the Female Changeling and was relayed to the engineers by Thot Pran, a Breen official. According to one report (from Kelvas V), the Breen would start installing the weapon on Jem'Hadar fighters within a week. () Although the Klingon fleet was able to make the needed adjustments against the weapon, the Federation and the Romulans were still unable to defend against the Breen. () Hence, the Breen were prevented from acquiring final victory for the Dominion only because the Klingon vessels were present. () When the Federation finally did create a defense against the energy-dampening weapon, they forced the Dominion fleet to retreat. Thot Pran expressed an extreme distaste for surrender, and required the reassurance of the Female Changeling that, instead of surrendering, they were actually regrouping and attempting to redouble their shipbuilding and replenishment efforts. ()
With the necessary countermeasures against the Breen's energy-dampening weapon obtained, the Federation Alliance was able to go on the offensive once again, choosing to try to invade Cardassia Prime itself. In hopes of raising the Breen's will to fight, the Female Changeling offered them control of Earth and Romulus if they succeeded in winning the battle. However, she then told Weyoun this was merely a political promise, designed just as motivation. While every Breen soldier on Cardassia was participating in a concerted search for Damar, the Breen, in the interest of maintaining their alliance with the Dominion, were positioned ahead of the Jem'Hadar by the Female Changeling, under pressure from Thot Pran.
During the ensuing Battle of Cardassia, the Breen were still able to inflict major casualties on the allies, even without the use of their energy-dampening weapon. Up to a third of the allies' entire fleet was destroyed during the battle, including the Romulan flagship, even though sabotage by the Cardassian rebellion resulted in the Dominion fleet being out of contact with their headquarters until midway through the battle. The Breen continued to fight for the Dominion until the end of the war, demonstrating a willingness to die for the cause which matched that of the Jem'Hadar. However, when the Cardassian forces switched sides mid-battle, the Dominion and Breen were forced to withdraw to Cardassia Prime. The Breen leaders left Dominion Headquarters in order to fight on the front lines, and both Damar and Weyoun were shot to death shortly thereafter. At the Dominion defense perimeter in orbit of the planet, the Breen were to be targeted by the Klingons, in a three-pronged attack that saw the Romulans, Cardassians and Starfleet focus on other targets.
After Odo convinced the Female Changeling to surrender, the Breen and their allies stood down, finally bringing an end to the Dominion War. As allies of the Dominion, Breen representatives were present during the signing of the Treaty of Bajor. ()
==== Continued aggression ====
Despite ceasing open hostilities with other major Alpha and Beta Quadrant powers, by 2381 the Breen had made at least one incursion into the Delos system and occupied the planet Brekka. This incursion was accidentally discovered by the crew of the . () However, it later emerged that Vice Admiral Les Buenamigo had prior knowledge of the Breen's presence on Brekka and had been setting the Cerritos up for a crisis that would "force" him to unveil the . Cerritos captain Carol Freeman was outraged when she learned this, as Buenamigo's actions had needlessly put her crew in mortal danger. ()
Before the Burn in the 31st century, there was some diplomatic contact between the Federation and the Breen, but no official contact afterwards. ()
===32nd century===
The Breen remained antagonists of the Federation in the 32nd century, by which time the Breen Confederacy had been succeeded by the Breen Imperium. In the late 32nd century, the Breen were embroiled in a civil war for control of the throne following the death of the Emperor. The factions were led by the six primarchs of the Yod-Thot royalty, among them Ruhn and . The Federation still had little information about the Breen beyond their hostile intentions. ()
During the conflict, Primarch Tahal occupied the planet for a time, despoiling its environment and decimating the native Kellerun population. ()
Unbeknownst to the wider galaxy, the son of the late Emperor and scion of the Imperium, L'ak, had betrayed his uncle Ruhn for his Human lover Moll, and fled into exile under an erigah bounty. The pair worked as couriers until 3191, when they stumbled upon clues to a Progenitor technology of immense power. Hoping that this technology could buy their freedom from the Breen, they competed with the to find pieces of a map containing its location.
After Moll and L'ak were apprehended by Starfleet, a confrontation ensued at Federation Headquarters with Ruhn, who sought to seize them as L'ak represented his claim to the throne. During an escape attempt, L'ak fatally overdosed himself on tricordrazine. Ruhn was prepared to wage war on the Federation, until Moll revealed herself as L'ak's wife and promised to deliver the Progenitor technology to him. With no better options, the Federation reluctantly agreed to release her to the Breen. ()
The Discovery subsequently clashed with Ruhn's dreadnaught at the Eternal Gallery and Archive over the final piece of the map. Captain Michael Burnham surrendered the map to Ruhn in exchange for his tergun oath to spare the Archive. Though Ruhn had no intention of honoring his word, he was deposed shortly after by a mutiny led by Moll and Lieutenant Arisar. ()
In an alternate timeline where the failed to free itself from a Krenim chronophage in time to stop Moll and L'ak, the Progenitor technology came into Ruhn's possession. A few weeks later, the Breen launched a devastating attack on the Federation. In 3218, Ruhn's dreadnaught was stationed near the wreckage of Federation Headquarters and Discovery. ()
== Biology ==
The Breen were hairless, pale green humanoids with two distinct forms: a solid form, and a gelatinous form in which their tissues were translucent and flexible. Breen culture taught that the gelatinous form was their true face, whereas the solid form represented a "weak" evolutionary throwback. ()
Breen internal physiology was quite different from that of most humanoids, and was largely unknown to Federation science even in the 32nd century. They had vital organs, but no blood or other liquid circulatory system. Exposure to a specific blend of subzero gases triggered a unique immune system response and somatic cell regeneration that could potentially allow a Breen to recover from life-threatening injuries. (; )
The Breen had male and female genders. They experienced pregnancy, often at a young age; newborn Breen were referred to as "hatchlings". (; )
The thoughts and emotions of Breen were not detectable by telepaths such as Betazoids. ()
===Rumors===
Even as late as the 32nd century, no one appeared to have seen a Breen outside of their suits, at least not without realizing it, as no one was aware that L'ak was actually a Breen due to L'ak never being seen using a refrigeration suit. According to Worf, no outsider had ever seen what a Breen looked like under their refrigeration suits and lived. () Due to this, there were many rumors regarding Breen.
Even shortly before the Dominion War was concluded, their appearance remained so completely unknown to their allies that Weyoun could not avoid wondering what the Breen looked like. () Ezri Dax once had a dream that featured a male Breen taking off his helmet to reveal he was actually Julian Bashir.
Worf firmly concluded that the species didn't have claws, although Ezri Dax wasn't sure of this belief. She, on the other hand, speculated that the Breen might be covered in fur, due to their home planet purportedly having a remarkably cold climate. () Dukat expected Dozaria's climate would be about fifty degrees too for the species, so he expressed extreme surprise at finding Breen guards on that planet. () However, while the intelligence reports available to Cardassian and Dominion leaders during the Dominion War reported their homeworld to be a frozen wasteland, Weyoun remarked (in his capacity as a diplomat) that the planet was really "quite comfortable." ()
== Society and culture ==
Breen entertained and taught their offspring with nursery rhymes. A particular example of a Breen nursery rhyme was made up of a heterophonic, five-line verse with an alternating tetrameter and pentameter structure. These were nonsensical phrases, strung together because they rhymed (at least to the Breen). Breen music which accompanied this nursery rhyme was written on a Lyxian scale. ()
Based on how algae paste tasted, Ezri Dax humorously speculated that the Breen were "horrible cooks." ()
Married Breen scarred themselves with matching symbols on their forearms. Marriage to a non-Breen was considered to be an "abomination", but even so the partners were legally entitled to stay together in life or death. ()
Breen culture was rigidly hierarchal. ()
The Breen rank structure included the title thot, which was implied to be greater than that of a Cardassian legate. () Other Breen worked as engineers, including at least four at the Kelvas facility. () The Breen Imperium of the 32nd century was ruled by a royal caste called the Yod-Thot, which included the primarchs. Ruhn was described as being "Breen Primarch of the Sixth Flight." () The Breen were originally ruled by a Breen Emperor, but after the last emperor's death the disparate branches of the royal bloodline began making competing claims for the throne, resulting in a civil war between six primarchs. Ruhn's nephew L'ak was the last direct descendant of the emperor and as such, he was considered to be the Scion of the Breen Imperium. If one of the primarchs could control L'ak, they would have a legitimate claim to the throne. ()
According to Commander Rayner, genocide was a necessity to the Breen and their version of the Prime Directive. ()
Breen medics, at least in the 32nd century, could be distinguished by a glowing symbol in the middle of their armor. ()
The Breen hold great reverence for their culture and history. () They have at least two known oath: a blood bounty called erigah which could only be released by the Breen themselves (); and a sacred oath called a tergun, where they swear upon the actions and the subjects within those words (and only within those), and breaking such an oath could cause the oath breaker to be hunted down by the other Breen for their dishonor. ()
A sarkaress was a Breen feast day. Multiple Breen going together were referred to as sarkmates and would partake in an oil bath together, something that seemed to be sexual in Breen culture. ()
=== Treatment of prisoners ===
The Breen were known to use slave labor, and at least some of these slaves were captured in raids on other species. When the Breen were using Bajoran slaves to mine dilithium ore, there were always at least eight guards within the mines. ()
The Breen were very prudent when dealing with prisoners. When capturing prisoners, the Breen typically stunned them from long range with their disruptors, rather than approaching them and risking close combat. When Worf and Ezri Dax were discovered by the Breen on Goralis while sleeping, the Breen used this technique to subdue them. The Breen also fed their prisoners a diet of algae paste. ()
Aboard starships, the Breen typically sent in three guards at a time when they wished to remove a single prisoner from a cell that was being shared with other prisoners. Although Worf made various attempts at escape, they all failed, including an attempt to persuade the Breen guards that Ezri was sick, as well as an attempt to short-circuit the door of their cell. When Worf attempted to attack the Breen guards, they used a type of neural truncheon to paralyze him. Even after he fell to the ground, partially paralyzed, two Breen guards continued to use the truncheons on him to ensure he would not get back up, before two guards removed Ezri from the cell. () In another incident, Worf simply showed signs of anger towards Weyoun and was again shocked by the neural truncheon. () On the other hand, a holographic Breen, enhanced by the Hirogen and participating in Iden's Rebellion of 2377, once helped restrain B'Elanna Torres, but did so in a way that was relatively very careful, taking Torres by the arm to a position where a force field could be activated around her. ()
To extract information from captives, the Breen used cortical implants, despite the fact that they caused extreme mental and physical side effects to the recipient, including severe pain and hallucinations. ()
=== Language ===
See: Breen language
== Science and technology ==
Given that most known humanoid species lived on class M planets with an average temperature far above the supposed temperature of Breen, the Breen were largely thought to have had to develop refrigeration suits in order to co-exist with others. () Underneath the suits, the Breen typically existed in their fluid state, believing that they had evolved beyond their solid state, although they were capable of taking on both. () Doctor Hugh Culber discovered in 3191 that the subzero gasses in the suits provoked a unique immune response in the Breen triggering their somatic cellular regeneration. ()
The Breen were known for their knowledge of sophisticated cold storage units, summed up in a statement Captain Benjamin Sisko once made: "If anyone knows how to keep things cold, it's the Breen." ()
By 2373, the Breen were among multiple species known by Starfleet to use organic-based vessels. () Some of their vessels were even believed to be fitted with cloaking devices. () During the mid-2370s, Breen interceptors utilized energy-dampening weapons. (, et al.) The expediency with which the Breen could mobilize large fleets of ships surprised Damar. () The Breen's piloting skills likewise impressed Nog. ()
The Breen were known to use type 3 disruptors, in common with the Romulans and Klingons. () The Breen also manufactured a portable hand-held cannon, the CRM 114, which was designed to target moving objects and surface emplacements. It was among numerous weapons dealt by Ferengi arms dealer in the mid-2370s. () A holographic facsimile of a pistol was almost used by the holographic Breen in Iden's Rebellion, moments prior to that Breen being deactivated. () In the 32nd century, they were capable of manifesting large Breen rifles and Breen staffs which doubled as a weapon. ()
The Breen made use of memory-probing technology, in the form of cortical implants, and neural truncheons for subduing prisoners. ()
By the late 32nd century, the Breen possessed massive dreadnaught-class starships which were so enormous that they massively dwarfed even the . The dreadnaughts were the Breen's most powerful warship class. ()
Breen dreadnaughts were equipped with a powerful energy weapon. ()
The Breen used base-duodeca coding which was really hard to hack and shield-tunneling technology to get soldiers through deflector shields. ()
== Mirror universe ==
In the mirror universe, Intendant once told Benjamin Sisko that Breen icicles were warmer than Professor . ()
== Individuals ==
;Named
* Gor
* L'ak
* Pran
* Ruhn
* Arisar
* 
;Unnamed
* Unnamed Breen
== Territory ==
== Appendices ==
=== Appearances ===
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** (Season 4)
** (Season 5)
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** (Season 7)
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* (Season 7)
* (Season 3)
*
** (Season 5)
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=== Background information ===
In the final draft scripts of and , the term "Breen" was listed in the pronunciation guide, phonetically notated as "BREEN".
In the Norwegian language, the term "Breen" means glacier.
Some of the actors and stunt performers to have worn the Breen costumes are Cathy DeBuono, Todd Slayton, Max Omega, Wade Kelly, Dennis Madalone, and Tom Morga.
==== Initial references ====
Ira Steven Behr once described the Breen, considering the references to them on , as "sort of a running joke" in TNG. () Marco Palmieri similarly reasoned that contemplating all the canonical facts about Breen biology is "enough to give the impression that as each new tidbit about the Breen was being conceived, little thought was given to the composite picture being created. And it may well be that this is exactly how the Breen started." ()
The first evidence of the Breen was in the TNG Season 4 episode , in which Data, during a meeting of the 's senior staff, mentions the Breen as one of "many races that are not empathically detectable." Both in that episode and the next installment to mention the Breen, TNG Season 5's , the Breen are cited as a possible culprit by Data, firstly in regard to Deanna Troi losing her empathic Betazoid abilities and secondly concerning the destruction of the SS Vico. In both cases, the Breen are found not to be the cause.
Jeri Taylor proposed exploring the Breen in an ultimately abandoned season finalé that would have ended TNG Season 6. In a memo which initially outlined the story (a document which was sent from Taylor to Michael Piller on ), the Breen were described as "a bellicose, brutal species who inhabit a distant but expanding empire." In the narrative, a Breen delegation was to be met and escorted to Earth by the Enterprise-D, formally establishing diplomatic relations between the Breen and the Federation. Although the Federation had long been happy that the Breen lived far from Federation space and had been expecting the species to be adversarial, the Breen had recently made the first tentative step toward establishing ties with the Federation. The unpleasantness of the species, however, became apparent to the Enterprise-D crew when the two groups met. They arranged an initial joint mission, whereby Starfleet scientists were sent on a Breen vessel to investigate a recently discovered phenomenon, but the ship suddenly vanished without explanation. In response, the Breen volatilely accused the Enterprise of being duplicitously responsible for the ship's disappearance, but the Enterprise then discovered the Breen ship, caught in an anomaly, and attempted to rescue it, the Starfleet crew jeopardizing their own vessel in the process. Jeri Taylor was of the opinion that using the story as an opportunity to introduce the Breen as a new adversary "would infuse new energy into the 7th season." In a revised version of the plot (relayed by Taylor to Piller in a memo dated ), she suggested that the Breen delegation meet with the starship , under Riker's command, rather than the Enterprise, though the latter still undertook the rescue attempt (much to Riker's chagrin). When Riker opted to go to the aid of the Enterprise while it was endangered due to the anomaly, the Breen were unsettled by this decision. The volatile Breen were thereafter encountered by Captain Picard, when he came aboard the Indiana, moments before he was blown out of the ship, through a rupture in its hull, and out into space. 
Although the Breen and their involvement in the palio on DS3 are discussed as essentially smalltalk between Picard and Vice Admiral Marcus Holt in TNG Season 7 entry , the Breen's function as suspects was not finished. They weren't referenced at all in the first draft script of , despite being mentioned on-screen in the final version of that film, wherein Riker cites them as potentially responsible for the attack on the Amargosa observatory, though this is later determined not to have been the case.
==== First appearance ====
When the DS9 writing staff required a villain for DS9 Season 4 episode "Indiscretion", an opportunity to physically depict the Breen presented itself. "We just struck on the idea to use the Breen," stated Robert Hewitt Wolfe. ()
In the script of "Indiscretion", the Breen were described as "tall, well-armed humanoids in dark, armored pressure suits which protect them from [...] harsh atmosphere." 
The hidden manner in which the Breen were portrayed – fully clothed, wearing masks and helmets – was influenced by the fact "Indiscretion" came very soon after episodes which featured large numbers of Klingons and Jem'Hadar (namely, and respectively). "I wasn't really in the mood to come up with a new alien race," explained Ira Steven Behr. "So I said, 'Let's not see them. Let's just put them in costume because they normally live in the cold." () An additional motive for Behr deciding that the Breen should appear in fully enclosed costumes was that this would cut down on make-up expenses. (Star Trek: The Official Starships Collection, issue 69, p. 17)
When the Breen helmets were being designed for "Indiscretion", it was decided that they would give viewers the suggestion of a snout, like that of an . () Terry J. Erdmann recalled about the Breen, "They were never supposed to be important at all, so when the wardrobe department first made Breen costumes, they were kind of simple; they just made a mask and put them on some guys who were going to stand in the background." ()
==== Interim ====
The word "Breen" was listed in the pronunciation guide for the final draft script of DS9 Season 5 installment , which noted that it "rhymes with 'green'." However, the term wasn't actually used anywhere else in that teleplay. 
The Breen were not referenced in the first draft script of fifth season outing , despite the species being talked about in the final version of that episode.
In the first draft script of , the Breen were referenced, by Jake Sisko, as having fought Bel Torthap, a writer whom Jake respected. This reference to the species lasted at least two versions of the first draft script: the original (dated ) and a revision (dated 8 July 1997). However, the Breen weren't mentioned at all in the final draft of the script for "Sons and Daughters" (issued on 11 July 1997). 
Thus, as of the start of DS9 Season 6 (in ), the show's writing staff didn't have any plans to feature the Breen in the series. However, Ronald D. Moore didn't rule out such a possibility, remarking, "We could explore them in the future." 
Mentioned above, a Breen named "Aaioa Uree" was originally to have appeared in DS9 Season 7 outing , but this idea was ultimately scrapped.
==== Return ====
At the start of a nine-episode arc that was designed to bring an end to Star Trek: Deep Space Nine, the Breen were brought into the Dominion War by the show's writers. Thus, the species went from having been used only "a handful of times" prior to DS9 Season 7 to becoming "major players" (as worded by First Assistant Director B.C. Cameron) in the first of those installments, . Their introduction into the conflict was motivated by the writers feeling sure that the Breen would heighten the stakes of the war. () Christopher L. Bennett observed that there was probably an additional reason why the Breen were introduced into the Dominion War. "I think the main reason for bringing in the Breen," he said, "was to establish that the Dominion saw Cardassia as disposable – not the partners they'd promised, but just a stepping-stone toward their conquest of the quadrant, to be tossed aside as soon as they'd outlived their usefulness (if you'll pardon the mixed metaphor). It was a motivator for Damar's – and Cardassia's – journey toward rebellion." As the writing staff didn't have the entire war worked out when they brought the Breen into it, they were uncertain how much would ultimately be learned about the Breen in the series. () Nonetheless, the Breen ended up as the last major villains to be introduced in DS9. Also, the fact that so little had been established about them, thus far, gave Designer John Eaves a feeling of particular freeness while designing the Breen ship, for "Penumbra". (Star Trek: The Official Starships Collection, issue 69, pp. 10 & 11)
The DS9 writing staff wanted to make the Breen seem highly mysterious. "We wanted to give these guys something special," commented Ira Steven Behr. "I couldn't make them the toughest guys in the galaxy – that's the Jem'Hadar. Or the most arrogant guys – that's the Cardassians. Or the most untrustworthy guys – that's the Vorta. So we decided to make them the most mysterious guys in the galaxy, with voices that really grate on the audience." Behr has also said that the Breen's distinctive, scratchy voice, which was first spoken in , was inspired by the guitar feedback on 's album . ()
When they decided to bring the Breen back, DS9's creative staff had to reuse the same costumes which had already been created for the species. "One day, the wardrobe department gets this call. 'Guess what? We're going to use the Breen," Terry J. Erdmann related. "Well, those masks that those poor actors are wearing have a long bill on the front, with only a tiny hole at the end for them to breathe. They snap on to the back, so they are difficult to put on and off, and the eye holes were in the wrong place, so they really couldn't see. But these almost unusable costumes were established, so they were stuck with them." () Not only did the costumes hamper breathing and seeing (the latter of which caused background extra Wade Kelly, when B.C. Cameron asked him to walk across a room, to repeatedly stumble noisily on set, during production on ), but wearing them also brought a host of other problems too. B.C. Cameron pointed out, "They're wearing big, clumsy boots, and their outfits are layered like an armadillo, making it very hard for them to move." Regarding the difficulties of using the Breen helmets, Steve Oster explained, "They're held together with magnets and they fall off any time someone bumps them. And before we redesigned them, the switches for the little blinky lights were on the inside of the helmet." This meant the helmets had to be removed from the actors every time the lights needed to be turned on. "And for some reason we never did figure out," continued Oster, "the nine-volt batteries only lasted minutes before they burned out." Thot Gor actor Todd Slayton considered "the biggest problem with the Breen mask" was the tiny hole for breathing, which he estimated was about eight inches away from the wearer's nose. He also noted that the viewing lens in the mask often steamed up quite quickly. ()
During the course of writing the Dominion War, the DS9 writers were very intent on establishing the Breen as extremely formidable, tough aliens. This inspired the introduction of the Breen energy-dampening weapon and the destruction of the USS Defiant, in . ()
The final Breen to be depicted (in live action) until Discovery was the holographic individual in . The final draft script of "Flesh and Blood, Part I" called for multiple holographic Breen to appear in the episode, although only one is present in the final version.
==== Uncertainties and trivia ====
Ultimately, Deep Space Nine never made clear how the Breen actually looked inside their costumes. Whereas First Assistant Director Lou Race "always" suspected the Breen looked similar to (owing to the beak-like part of their helmets), Make-Up Supervisor Michael Westmore admitted that he wasn't really sure how they looked. However, he also reflected, "I actually had an unused head in the lab that would have been great. I thought we could put a little bit of a snout onto it, so we could justify the snout on the helmet. But we never had the opportunity to show one of them." ()
It was also left unclear whether anyone had ever seen a Breen and survived the experience. In "'Til Death Do Us Part", Worf states, "No one has ever seen [a Breen] and lived to speak of it." However, "Indiscretion" implies that Kira and Dukat must have gotten a look at a pair of Breen whose uniforms they stole. Compounding the continuity problem, Kira is implied as having dispatched another Breen, again for his uniform, in DS9 series finalé . In hindsight, Ronald D. Moore regarded this continuity glitch as one of numerous frustrating details that, due to their sheer quantity, the creative team hadn't managed to keep track of. On the other hand, Ira Steven Behr proposed an in-universe explanation, saying, "There's nothing in those helmets. I don't think there's a guy in there, which is something we never got around to saying." After a pause, he added, "Or maybe there's a little slug, some tiny little creature in there. I never wanted them to be humanoid in any way." () Despite this, not only did the aforementioned script of "Indiscretion" regard the Breen as "humanoid" but so do the reference works and Star Trek: Star Charts (p. 35) as well as the StarTrek.com database entry about the species. 
The model for the Breen helmet closely resembles a Ubese Bounty Hunter suit that Princess Leia wore to Jabba the Hutt's Palace in Star Wars Episode VI: Return of the Jedi. 
==== 32nd century return and unmasking ====
Glenn Hetrick of expressed an interest in the Breen appearing in that series without their masks. Hetrick commented, "No one in the universe, as per Worf, has ever seen what they look like under the refrigeration suits. So, that is definitely – as many times as I can put it forth – I want to get one of those refrigeration suits off and see what the Breen look like." 
Carlos Cisco lobbied hard for the Breen to appear in DIS Season 5. "The Breen were one of my strongest pushes for the season. Early on a couple of us who were really into the lore were asked for ideas on the season big bads and [staff writer] Eric [Robbins] was pushing for the Vidiians and I was like we should do the Breen.” Because, A: They’re not going to have horrible makeup, and B: We can just put a bunch of big guys in suits and they don’t need to talk. Being mindful of the COVID protocols, the suits and masks would be really great. And then there were all the possibilities for the Breen because in every season Discovery is trying to do something we have never seen before. And getting to unmask the Breen was a really big privilege."
Regarding their appearance, Cisco said, "I don’t remember where in the process we landed on “gelatinous” but when we hit the art team with that they came back to us with deep sea fish like the Barreleye Fish with a see-through head. We got really excited about that. So we started talking about what is this species? Why do they wear the suits? So, the thing we landed on is they have this soft gelatinous form and also a hardened form. Our thinking was that the Breen came up on a very harsh planet with a harsh environment. So they developed a way to protect themselves which was hardening their outer shell into basically a skin, but that takes an immense amount of concentration and energy, making them slower, more sluggish, less intelligent, basically. Over time, they compensated for that by creating the refrigeration suits. Then culturally, it became anathema for them to display that solid face, especially to outsiders, because it was essentially a sign of weakness." 
==== Reception ====
The writers of Star Trek: The Official Starships Collection (issue 69, pp. 16 & 17) approved of the Breen. They regarded them as "vitally important to the Dominion War" and further remarked, "Despite the hazards of the costume, the Breen proved a tough and formidable adversary that ratcheted up the threat to the Federation in the final months of the Dominion War. Without them, the final story arc would not have been so tense and compelling."
Marco Palmieri wrote, "You have to hand it to the Breen: For a civilization that started out as a sometimes-mentioned but never seen running gag on The Next Generation, they eventually came incredibly close to handing the Founders a decisive victory in the Dominion War. Along the way, the Breen not only destroyed the Starship Defiant, they succeeded where no other enemy empire had before: attacking Starfleet Headquarters on Earth. Even the Klingons had reason to fear them [...] [considering] an Imperial fleet sent to conquer the Breen homeworld was never heard from again. That's not a bad résumé as Star Trek villains go." ()
 cited the Breen as his favorite race. ()
=== Apocrypha ===
In the Zero Sum Game, the Breen are revealed to be comprised of several different species, with "Breen" as the name of a society, rather than a single species. The primary reason for this is to judge individuals on their skills and abilities rather than their physical appearance. In reality, however, this approach was taken by Zero Sum Game author David Mack because he believed that trying to reconcile all the canonical "facts" about the Breen's physiology would otherwise be impossible, as he thought there were too many discrepancies. ()
Among the species in the Breen Confederacy mentioned in Zero Sum Game, only four were mentioned by name and described in some detail, and an additional fifth species was described in the novel Plagues of Night. Two more species were named in the novels Disavowed and The Hall of Heroes. They include:
* The , a humanoid species and a founding species of the Confederacy, who possessed (in the case of the character Chot Nar) bronze-tinted skin, white hair, and jade-colored eyes.
* The , a furred, lupine humanoid species whose snouted facial structure served as the inspiration for the archetypical Breen helmet design.
* The , a large, powerful humanoid species who often served in the Confederacy military thanks to their strength. They are noted to possess four-lobed brains that make their minds difficult to read, as well as an unspecified number of hearts.
* The , a humanoid species whose bodies possessed no blood and evaporated when exposed to normal M-class atmospheres, requiring them to wear actual refrigeration suits to function outside of their regular environment. They also served commonly in the Confederacy military alongside the Paclu.
* The , a humanoid species with cleft arms and legs with highly accurate sensory organs located along their lengths that granted them exceptional tactile abilities, making them highly effective engineers. The enhanced sensory abilities of the species also rendered them prone to motion sickness.
* The , a humanoid species that can easily mingle among the peoples of the Federation. Author David Mack has said that this is actually a mistake, which is meant to refer to the Silwaan. 
* The , a humanoid species with no nose and a pale, scaly complexion.
The Breen were members of the Typhon Pact, an alliance of several powers antagonistic towards the Federation, which allied them with the Romulans, the Tholians, the Gorn, and the Tzenkethi.
Decipher's supplement explained the discrepancy over whether anyone had seen a Breen and lived by establishing that the Breen disintegrate upon exposure to atmosphere.
The video game Star Trek: Conquest features Breen as one of the people groups which players can assume the role of. Of the three types of commanders available – attack, defense, and movement – the Breen only have defense (2) and movement (1) available.
In Star Trek Online, the Breen were the main antagonists in a short episode arc. During the arc, the Breen invaded space, hoping to acquire technology.
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