Nymeria is a female direwolf adopted by Arya Stark. She was found along with her littermates, Ghost, Grey Wind, Shaggydog, Summer, and Lady, shortly after their mother was killed by a stag.

In A Game of Thrones, Nymeria assaults Joffrey I Baratheon after a swordplay game goes awry. The attack is blamed on Lady, who is killed by Eddard Stark on the order of the king. Meanwhile, Arya and Nymeria flee, and when Arya is found later, Jory Cassel convinces her to chase Nymeria off so that she won't be killed as well.

In A Clash of Kings, Arya hears about a female direwolf who has been leading a fearless pack near the Gods Eye.

In A Storm of Swords, Arya has become a warg and Nymeria leads her to Catelyn Stark's dead body.

In A Feast for Crows, Arya continues to have wolf dreams, and man-eating wolves are rumored to roam near Riverrun.

In A Dance with Dragons, Ghost encounters Nymeria leading the fearless pack.