Geirrvif at Valhallas has challenged you to defeat Sigrid Iceborn. Should you succeed, speak with Gjonner the Merciless overlooking the southern lip of Valhalas.
An old foe of yours has returned: Sigrid Iceborn. Perhaps you remember besting her in a duel upon the Savage Ledge?
No matter, she certainly remembers you. She's insisting upon a chance to prove herself once more.
Personally, I think it's more a chance for revenge, but that too can be useful in this place.
I leave it up to you, [player]. Will you face Sigrid Iceborn once more?