Hallberta Thorstardottir is the daughter of Thorstar Ulfbjornsson and younger sister to Arnbjorg Thorstardottir. She never thought she’d have to share a man with another woman, but she knew she’d marry Gili. Especially after her sister, Arnbjorg went on to marry his older brother Saxi. Not to mention that Arnbjorg shared Saxi with another woman. She thought she couldn’t do that until she saw that Gili didn’t just have eyes for her but also for her close friend Jofrid Sigviddottir. Originally, she was jealous and the two close friends quickly became rivals. However, neither was willing to budge and eventually the two women came to an agreement. They decided to share Gili. Before they knew it, they were all wedded and eventually Hallberta became pregnant and eventually gave birth to Hilde, their daughter.
Even though Hilde was her own daughter, she made sure her sister-wife and close friend Jofrid also felt like her mother. They worked together to raise Hilde the best way possible, sharing the responsibilities and duties of motherhood and it strengthened the bond between them and their husband Gilli.