Thrynga was a mountain giantess and the sister of Thrym.
Thrynga appears to Magnus and his friends to escort them into the giants' cavern at Bridal Veil Falls. She attempts to get the Skofnung Sword from Magnus, and is visibly annoyed when he points out that he can't give it away until during the wedding ceremony. She bides her time during the wedding.
Thrynga was a malicious, ambitious and greedy person. She was willing to kill her own brother to achieve power.
Thrynga was a seven foot tall giantess with hair stark white done in two braids. She wore a dress stitched entirely from white furs. Thrynga had bulging eyes the size of oranges and a nose that looked like it had been broken several times. Her lips and teeth were stained black.