- "It was reforged from Ned Stark's sword. You'll use it to defend Ned Stark's daughter."
- ―Jaime Lannister to Brienne of Tarth
Oathkeeper is one of two Valyrian steel longswords made from Ice, the greatsword of House Stark, under orders of Lord Tywin Lannister. While initially given to Jaime Lannister by Lord Tywin with the intention of making it an heirloom of their house, Jaime instead gave it to Brienne of Tarth for the task of rescuing Sansa Stark. Its sister blade is Widow's Wail.
Tywin gives the sword to his son Jaime, intending for him to be released from his vows as Lord Commander of the Kingsguard and rule over Casterly Rock in his stead. When Jaime refuses, Tywin lets him keep the sword anyway and tells him that a one-handed man without family (implying Jaime had been disowned) needs all the help possible.
Following King Joffrey's death, Jaime tasks Brienne with finding Sansa Stark and get her somewhere safe before Cersei locates her. As a parting gift he gives her the sword, as he knows it was reforged from Ice, so she can protect Ned Stark's daughter with Ned Stark's own blade. She considers a name for a few moments, before choosing "Oathkeeper".
When Brienne and Podrick encounter Arya Stark and Sandor Clegane, Oathkeeper's obvious Lannister qualities (the hilt is a golden lion) cause Arya and Sandor to be suspicious of Brienne. When the situation turns hostile, Brienne uses Oathkeeper in combat for the first time against Sandor. However, she wins the duel by knocking Sandor off a cliff after brutal hand-to-hand combat.
Still in the Vale, Oathkeeper remains in Brienne's possession. After an encounter with Sansa Stark and Petyr Baelish turns hostile, Brienne kills three of the guards that attempt to pursue them with Oathkeeper. The Valyrian steel sword is strong enough to slice through the sword of one of the guards.
Brienne and Podrick arrive to the Wolfswood in time to rescue Theon Greyjoy and Sansa Stark from the Bolton soldiers sent by Ramsay Bolton after they escaped from Winterfell. Brienne uses Oathkeeper to slay several soldiers while Podrick dispatches the rest. After the battle, Brienne lays Oathkeeper at Sansa's feet and pledges fealty to her. Sansa accepts Brienne's service.
In the booksEdit
In the A Song of Ice and Fire novels, the sword is forged by Tobho Mott along with Widow's Wail. The sword has black and red ripples through the steel. Its scabbard glitters gold and is decorated with a row of lion's heads and smoldering red rubies. The pommel has a golden lion's head with ruby eyes that shine like two red stars.
Jaime is angry when the sword is given to him, thinking that it is a cruel joke of his father and uncle given that such a blade would be wasted on him, since he has lost his right hand (akin to giving expensive boots to a legless man). Kevan is upset to hear how Jaime feels about the sword, saying the gift was heartfelt, but Jaime is not mollified.
After returning to King's Landing, a short time after the Purple Wedding, Jaime and Brienne are stopped by Ser Loras Tyrell, who believes that Brienne was responsible for Renly's death. Jaime orders Brienne to be locked up for her own protection, thus when Jaime gives her sword she is in a tower cell, not the White Sword Tower. He also suggests the name "Oathkeeper" to her, claiming it is appropriate that she will be defending Ned Stark's daughter with Ned Stark's own steel.