Brienne of Tarth first appears as a recurring character in seasons two and three of Game of Thrones, and then becomes a more central character in the fourth and fifth seasons. She is excellently portrayed by Gwendoline Christie.
Brienne is the daughter and only child of Lord Selwyn Tarth of Evenfall Hall. Her mother died when she was very young, and Brienne has no memories of her. Lord Selwyn rules the Island of Tarth, which produces all of the sapphires in Westeros. Initially, Brienne was supposed to make a noble marriage to ensure the continuation of the line, but her appearance and habits make that highly unlikely.
In appearance, Brienne is very masculine and thus considered very unattractive. She keeps her hair short and is both muscular and flat-chested. From far away it is very easy to mistake her for a man. Brienne generally wears men’s clothing and has several scars from the fights that she has gotten into. She became interested in fighting from a young age, and her biggest dream is to become a knight.
In season two she begins fighting for Renly Baratheon after winning her way into his forces by defeating his best champions. While at his camp, she meets Catelyn Stark and becomes her sworn sword. After Winterfell is taken by Theon Greyjoy, Briene continues to protect Catelyn along with their hostage Jaime Lannister. Her loyalties clearly lie more with Catelyn than with House Stark or any other sides in the conflict raging through Westeros.
While Brienne is guarding Jaime, the two develop a close relationship. Despite this fact, Brienne is still in charge of Jaime’s captivity while transporting him to King’s Landing. At one point Jaime attempts to escape and is defeated in a fight with Brienne. The two are captured by Lord Bolton, and Jaime saves Brienne from being raped by letting them know her noble status. Eventually the two are freed, and although they part ways for a while they remain in close contact.
After Sansa Stark escapes from King’s Landing, Jaime asks Brienne to find her and keep her safe. Jaime’s squire, Podrick, is sent to travel with her and help her in her quest. They are sent to the house of Lisa Arryn by a somewhat friendly innkeeper who has a suspicion of where Sansa might be. They don’t find Sansa, but they do find her sister, Arya, accompanied by the Hound. Brienne kills the Hound, but Arya runs away during their battle.
Brienne and Podrick begin to travel to Castle Black to continue their search for Sansa, but at an inn along the way they discover Sansa dining with Littlefinger. They approach her to offer protection, but are rejected and have to escape to avoid being killed by Sansa’s guards. Brienne and Podrick escape safely, and continue traveling until they reach Winterfell. The two, by this time, have formed a close bond and Brienne has revealed that she was in love with Renly.