Elsa Fen ran from her father’s hold-fast which was under attack by the nightwalkers. Seeing Jack Frost’s advertisement, she went in search of him and hoped he could help her family. By the time they got to her father’s castle, the entire place was empty. But before anything could be done, the nightwalkers attacked and captured them. However, in a small way, they helped reunite her with her family. Much to Jack’s surprise their leader Wruk Buk Tuk had his people go through the humans to find him. He needed his help to stop a sorcerer who had been controlling his people. Jack agreed on the condition his people would stop killing and eating humans, and that MacDuff would help make a peace treaty with them and Elsa’s father.
After a long battle, he defeated the sorcerer and was now becoming known as a hero. Much to his surprise however, Elsa was more than a little grateful as she rewarded him with a kiss. His first kiss, and as her family began to rejoice, Jack was confused. MacDuff later explained that here when he “saved” the girl, he gets the girl. Meaning he and Elsa would be engaged to be married. While Elsa was thrilled, Jack wasn’t so eager. While he did appreciate Elsa for helping him become a hero, he didn’t want to get married right away. So he and MacDuff later crept out at night. Its unknown if she ever got married or if she felt angered by him leaving.
She’d appear near the Jack of Fables The End when she and Brak felt something calling her. She’d meet up with Pecos Bill, both were confused by the sight of the battle. Its unkown of what happened to her or Brak. They were either killed off screen or some how survived. If they did, they most likely gave Jack Frost and MacDuff a proper burial.