As of Gentleman Jole and the Red Queen, Gregor Vorbarra is the current Emperor of Barrayar. He consequently rules over Barrayar, Komarr, and Sergyar, the three planetary bodies of the Barrayaran Empire.
His father was the late Crown Prince Serg, and his grandfather was Emperor Ezar Vorbarra. They had both died by the time Gregor was five, therefore, Admiral Lord Vorkosigan ruled as Regent until Gregor reached the age of majority. This was not the last of Gregor's woes as a child, as he became a pawn in a power struggle between the Regent and the usurper Count Vordarian, a struggle that cost the life of his mother, Princess Kareen Vorbarra.
Gregor's name is an apparent inconsistency in the world-building of the Vorkosigan Saga. Vor tradition provides that the first-born son has the paternal grandfather's first name, which in this case is Ezar.
Gregor is a fairly progressive and liberal emperor, but must remain even-handed in order to rule effectively. He is also Count Vorbarra, and technically has a vote in the Council of Counts. By tradition, he does not exercise that vote except to break a tied ballot, much like the vote of the Vice President of the United States in the United States Senate. Psychologically, Gregor lives in fear that he carries the madness that afflicted his relatives, particularly his sadistic father Crown Prince Serg, but also the mad Yuri Vorbarra and his relations in the Vorrutyer clan, best (or worst) exemplified by Serg's companion in depravity, Ges Vorrutyer. While capable of great personal warmth, he maintains iron control in most situations, projecting an air of deep calm.
When he came of age, Gregor discovered the truth about the depravities committed by his father, and was so upset he eluded his bodyguards while on a state visit to another planet in the Nexus, and went missing for a time before Miles Vorkosigan found him (The Vor Game).
He is married to Laisa Toscane, a Komarran scion of one of the richest and most powerful families on the planet. The marriage was a critical move (though they were genuinely in love, so the marriage was not merely political) as it served to show a unity between Barrayar and its conquered world of Komarr. (Though some feared it would just be an eternal symbol of Komarr "getting screwed" by Barrayar.)
For many Vor, the marriage was important because it meant Gregor would start producing Imperial Heirs and thus relieve tensions that, should something happen to Gregor, there would be a civil war, as every Vor with a claim to the Imperium would come forth. For Gregor the marriage meant a chance to have children with a woman who was not Vor, and therefore free of the genetic taint that curses the high aristocracy.
Initially introduced to the bachelor Emperor when she accompanied her date, Duv Galeni, to a dinner party at the Imperial Residence, Laisa impressed Gregor with her bold and succinct attempt to lobby him directly for trade concessions during the course of the meal. Gregor later invited her to an intimate luncheon in which he thrilled her by arranging her first horseback ride, on a beautiful white mare, which could be construed as the beginning of their courtship.
Laisa is also described as "maternal", short, and a little plump, unlike the fashionably tall, willowy Vor women Gregor was introduced to by Lady Alys Vorpatril, his social secretary. Laisa's eyes are described as being beautiful, a shade that is not quite blue, nor quite green. Despite her lack of svelte proportions, she is still described as classy and stylish, although generally attired in Komarran-style garments. Lady Alys would ruefully note after her betrothal to Gregor, that it should have been obvious that a man who lost his mother at the age of four would be attracted to maternal-looking women; but more importantly, Gregor wanted to ensure that his children would not be insane like one of his ancestors (Mad Emperor Yuri), and he welcomed genes from outside the Vor gene pool.
Laisa is highly intelligent, and has an advanced education in financial and business affairs. Prior to her marriage, she served as a lobbyist and representative in Vorbarr Sultana for her family's business interests. It was stipulated in their marriage contract that any children of the union were to be gestated in uterine replicators, and not by the method preferred by the more conservative among the Vor caste of "body births".
Many Komarrans (and many Barrayarans, for that matter) view the marriage as shrewd politics on the part of Gregor, symbolizing a union of two of the slightly antagonistic component societies of the Barrayaran Imperium. To further strum political sensibilities, Gregor decreed that the reconstructed and enlarged Komarr Soletta, a large orbital array of mirrors augmenting the solar light reaching the planet's surface, which is necessary in Komarr's long-term terraforming project, be deemed a wedding present to his wife, and symbolically to the planet Komarr from Barrayar.
Gregor and Laisa have several children together, who are described as "scarily smart" by Armsman Roic. (CryoBurn).
- The entire Vorkosigan Saga