Breen

The Breen homeworld is called Breen, according to the 1999 Star Trek: Deep Space Nine episode "'Til Death Do Us Part", and was said to be a frozen wasteland in "Indiscretion". However, in the 1999 episode "The Changing Face of Evil", it was stated by Weyoun that it is in fact rather temperate. Among the Breen, pregnancy at a young age was a common occurrence, according to "Elogium", a 1995 second season Star Trek: Voyager episode, though it has not been established what is considered "young" in the Breen culture. The Breen have no blood.[3] How the functions normally carried out by blood in other species are carried out in Breen physiology has not been revealed. Although the Breen diet is unknown, Lieutenant Commander Worf and Ezri Dax were given algae paste when they were prisoners of the Breen in "'Til Death Do Us Part".
Historically, the Klingons were among the first to discover the consequences of underestimating the Breen. As revealed in "'Til Death Do Us Part", 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 have a saying: "Never turn your back on a Breen". This adage was first stated (and illustrated) in the 1997 fifth season Deep Space Nine episode "By Inferno's Light", in which a captive Breen grabbed a disruptor pistol from the holster of a Dominion guard, whose back was turned to him in a Dominion asteroid prison, and used it to disintegrate two Dominion guards at the same time as one of them killed the captive. The Breen in question had not done anything besides sit quietly up until that point, giving no indication that he would be a threat.
The Breen established the isolated Breen Confederacy in the Alpha Quadrant (the quadrant of the Milky Way in which Earth is located, as well as the homeworlds of the Ferengi, Cardassians, and portions of the Klingon Empire and Romulan Star Empire). The Breen established outposts near the Black Cluster, according to the 1992 fifth season Next Generation episode "Hero Worship". They also established mining facilities consisting of Breen guards and slaves kidnapped from spaceships, such as Tora Ziyal, the half-Bajoran daughter of the Cardassian Gul Dukat, whose ship, the Ravinok, had crashed on the planet Dozaria, which was controlled by the Breen, as established in "Indiscretion".
In "Hero Worship" it is mentioned that they have always been politically nonaligned. They later become a powerful ally of the Dominion, a Gamma Quadrant empire, during the Dominion War that was fought during the final two seasons of Deep Space Nine. The Breen were revealed to have allied with the Dominion in "’Til Death Do Us Part", the second episode of the nine-episode story arc that served as the final story arc of Deep Space Nine in 1999. After this occurred, the Breen attacked Earth, destroying parts of San Francisco before being repulsed. They also proved a powerful foe during the Battle of Chin'toka, in which they fought alongside the Cardassians and Dominion against an alliance of the Federation, the Klingon Empire and the Romulan Star Empire. During this battle, the Breen helped destroy a fleet of the alliance's ships, including the USS Defiant. The Breen also assumed great responsibility in military matters. The leading representatives of the Breen Confederacy, called "Thots" (which Damar, leader of the Cardassian military, compares to his own rank of Legate, in the episode “Strange Bedfellows”), such as Thot Gor and Thot Pran, were given more powers, much to the bitterness of Damar, whose own people had earlier joined the Dominion. This was one of the factors which led to Damar changing sides and leading a rebellion to free Cardassia. After the Cardassians turned against the Dominion, the Dominion and the Breen were defeated in the Battle of Cardassia Prime in Deep Space Nine's series finale, "What You Leave Behind". The Breen's status with respect to the Dominion after this has not been mentioned onscreen since "What You Leave Behind", and is therefore unknown in canon.

Technology and equipment

In "Scorpion", 1997 the third-season finale of Star Trek: Voyager, Lieutenant Tuvok states that the Breen use organic technology in their ships when discussing the bio-organic starships of Species 8472. Their ships are armed with cloaking devices and disruptor-type weapons, according to "Hero Worship".
In Star Trek Generations Riker mentions the Breen as one of only three species with access to Type-III hand-held disruptors.
During the Battle of Chin'toka, a Dominion War battle that occurred in the episode "The Changing Face of Evil", the Breen employ an energy-damping weapon that could shut down all systems on Alliance ships. The Klingons subsequently discover an engine modification that renders Klingon ships immune to this weapon, though it does not work on Federation or Romulan ships since they are powered differently. The Breen used this weapon to great effect, completely immobilising the USS Defiant, and a fleet of alliance ships, allowing the Breen to destroy them at their leisure.
The helmet of the Breen suits consists of a visor that either glows green, or has small green and red lights on it,[4] and a detachable "beak". The Breen's suits come in two types. The first is a standard suit that is worn by most of the Breen. The second is a more ornate version worn by Thots or other officials that has gold lining and distinctive gold stripes running down the top of the helmet and the "beak", as seen in later episodes of Deep Space Nine, such as "Strange Bedfellows".
The non-canonical book Legends of the Ferengi claims that the Ferengi were sold warp technology by a Breen they called "the Masked Breen" (because they did not know the Breen all wore masks). In return, they gave the Breen both poles of Ferenginar, several comets, and a frozen moon.