Satrina was the lover of Kartag, the giant who was commanded by the Norns to guard the Twilight Well. Apparently their relationship lacked a bit of communication, because Satrina was unaware of her lover’s special duty to the Norns.
When she could not prevent Thor and his friends from advancing on the well, she led them directly to Kartag, hoping that he would finish them off.
In the end, the Fates did not wish Thor to be destroyed, but were testing him to see if he was worthy of the water that he sought.
Not recognizing the Norns, Satrina brashly attacked them, but obviously to no avail. They overlooked her foolishness and sent her lover to help Thor fight Mangog.