Guldwyn was the first child and daughter of Fengel of Rohan and Éolind Cyninge, making her the Princess of Rohan during the late-Third Age. She was also elder sister of Léoffléd and Thengel, and ever since her siblings were born, Guldwyn would look after them since she was very kind in spirit. After her mother passed away from childbirth, Guldwyn saw how her father was starting to react and change his personality. She was one of those that chose to look after Léoffléd and Thengel, but a few years later, she suddenly fell ill and passed away around her love ones.