Sergyar is one of the three planets that comprise the Barrayaran Empire

Barrayar

Barrayar is a science fiction novel by Lois McMaster Bujold. It was first published as four installments in Analog in July–October 1991, and then published in book form by Baen Books in October 1991. Barrayar won both the Hugo Award for Best Novel and the Locus Award for Best Science Fiction Novel...

 in the Vorkosigan Saga

Vorkosigan Saga

The Vorkosigan Saga is a series of science fiction novels and short stories set in a common fictional universe by American author Lois McMaster Bujold. Most of these were published between 1986 and 2002, with the exceptions being “Winterfair Gifts” and Cryoburn...

. The other planets are Barrayar

Barrayar

Barrayar is a science fiction novel by Lois McMaster Bujold. It was first published as four installments in Analog in July–October 1991, and then published in book form by Baen Books in October 1991. Barrayar won both the Hugo Award for Best Novel and the Locus Award for Best Science Fiction Novel...

 and Komarr

Komarr

Komarr is a planet in Lois McMaster Bujold's Vorkosigan Saga series of novels and stories.Discovered centuries prior to the Vorkosigan Saga, Komarr is undergoing a major terraforming project to make the outside air breathable. During this centuries-long program, the Komarrans are confined to domed...

. The entire planet has been said to be the personal property of Barrayaran Emperor Gregor Vorbarra

Gregor Vorbarra

Gregor Vorbarra is the Emperor of the Barrayaran Imperium in the sci-fi series the Vorkosigan Saga by Lois McMaster Bujold.As of CryoBurn, Gregor Vorbarra is the current Emperor of Barrayar...

.

Discovery

Sergyar was first discovered by Barrayar

Barrayar

Barrayar is a science fiction novel by Lois McMaster Bujold. It was first published as four installments in Analog in July–October 1991, and then published in book form by Baen Books in October 1991. Barrayar won both the Hugo Award for Best Novel and the Locus Award for Best Science Fiction Novel...

 shortly before the Escobar War. It is the site where Cordelia Naismith

Cordelia Naismith

Cordelia Naismith is the name of two fictional characters by Lois McMaster Bujold. One is the titular character from a Victorian era Sherlock Holmes short story entitled "Adventures of the Lady on the Embankment" included in her anthology Dreamweaver's Dilemma...

 and Lord Admiral Aral Vorkosigan

Aral Vorkosigan

Aral Vorkosigan is a fictitious character from Lois McMaster Bujold's Vorkosigan Saga series. Known throughout this science fiction universe as “The Butcher of Komarr,” he dominates the imagination of the two main point-of-view characters in the Vorkosigan Saga, Cordelia , who becomes his wife,...

 first met when her Betan

Beta Colony

Beta Colony is an important planet in Lois McMaster Bujold's science fiction series the Vorkosigan Saga. The planet's biome is almost entirely desert, described as "screaming hot," and the colony itself exists primarily underground.The concept of Beta Colony was first created and introduced in...

 Astronomical Survey ship landed a party to explore and catalogue the planet and its biome, unaware of Barrayar's earlier territorial claims on the planet.

Strategic importance

Sergyar is strategically important because it is a link from Komarr

Komarr

Komarr is a planet in Lois McMaster Bujold's Vorkosigan Saga series of novels and stories.Discovered centuries prior to the Vorkosigan Saga, Komarr is undergoing a major terraforming project to make the outside air breathable. During this centuries-long program, the Komarrans are confined to domed...

 to Escobar, and then Beta Colony

Beta Colony

Beta Colony is an important planet in Lois McMaster Bujold's science fiction series the Vorkosigan Saga. The planet's biome is almost entirely desert, described as "screaming hot," and the colony itself exists primarily underground.The concept of Beta Colony was first created and introduced in...

. This opens up trade in the wormhole nexus significantly for Barrayar. It was the site of massive caches of ordnance and other materiel for Barrayar's abortive attempt to invade and conquer Escobar.

Native life

Native life on Sergyar seems to have a general radial symmetry, with most lifeforms having six limbs or appendages. While there are no known native sentient life forms, there is a diverse ecology. Various species mentioned include large predators referred to as 'fuzzy crabs' that hunt in packs, and their 'hexapedal' herbivorous prey - large, six-footed grazing animals.

Smaller creatures, radial in design, seem to fill the ecological niches filled by insects on Earth. There are also mentions of airborne lifeforms, similar in appearance to jellyfish, that float through the atmosphere, supported by gas-filled sacs, that descend from above to leech blood from larger, moribund lifeforms. The gas is mostly hydrogen, and will explode if exposed to fire.

In later books, there are mentions of a Worm Plague on Sergyar; its survivors have puckered, swirling scars on their skin.

Name

According to the naming scheme of Barrayar, the particle "-yar" likely means "planet", "world" or something similar. Thus, Sergyar was named for Crown Prince Serg, the one-time heir apparent

Heir apparent

An heir apparent or heiress apparent is a person who is first in line of succession and cannot be displaced from inheriting, except by a change in the rules of succession....

 to Emperor Ezar

Ezar Vorbarra

Ezar Vorbarra is a minor character in Lois McMaster Bujold's sci-fi series, the Vorkosigan Saga.Ezar Vorbarra was the Emperor of Barrayar during the time of the novel Shards of Honor. His son, Crown Prince Serg, was killed during the Escobar War , leaving five-year-old Prince Gregor as the only...

 Vorbarra

Vorbarra

Vorbarra is a surname in the science fiction series the Vorkosigan Saga. It is the surname of the Emperors of Barrayar and the namesake of the planet.The emperors of Barrayar have all carried the name Vorbarra...

 and father of now Emperor Gregor

Gregor Vorbarra

Gregor Vorbarra is the Emperor of the Barrayaran Imperium in the sci-fi series the Vorkosigan Saga by Lois McMaster Bujold.As of CryoBurn, Gregor Vorbarra is the current Emperor of Barrayar...

 Vorbarra

Vorbarra

Vorbarra is a surname in the science fiction series the Vorkosigan Saga. It is the surname of the Emperors of Barrayar and the namesake of the planet.The emperors of Barrayar have all carried the name Vorbarra...

. Prince Serg died in the Escobar War.

Government

The seat of its government is a settlement dubbed "Chaos Colony." In the later series, Count Aral

Aral Vorkosigan

Aral Vorkosigan is a fictitious character from Lois McMaster Bujold's Vorkosigan Saga series. Known throughout this science fiction universe as “The Butcher of Komarr,” he dominates the imagination of the two main point-of-view characters in the Vorkosigan Saga, Cordelia , who becomes his wife,...

 and Countess Cordelia Vorkosigan governed Sergyar as Viceroy

Viceroy

A viceroy is a royal official who runs a country, colony, or province in the name of and as representative of the monarch. The term derives from the Latin prefix vice-, meaning "in the place of" and the French word roi, meaning king. A viceroy's province or larger territory is called a viceroyalty...

 and Vicereine, respectively. A steady flow of immigrants from Barrayar

Barrayar

Barrayar is a science fiction novel by Lois McMaster Bujold. It was first published as four installments in Analog in July–October 1991, and then published in book form by Baen Books in October 1991. Barrayar won both the Hugo Award for Best Novel and the Locus Award for Best Science Fiction Novel...

 and Komarr

Komarr

Komarr is a planet in Lois McMaster Bujold's Vorkosigan Saga series of novels and stories.Discovered centuries prior to the Vorkosigan Saga, Komarr is undergoing a major terraforming project to make the outside air breathable. During this centuries-long program, the Komarrans are confined to domed...

have made new homes on Sergyar, many of whom were former residents of the Vorkosigan District.