A Ruin Child found sleeping in the ruins near Saudrick by Crevanille, Remus, Lumis, and Vallery. An angel attacked the ruins as they found her and they quickly had to take her and escape. Because she was awakened suddenly and improperly, she could not remember anything but her name. However, she recognized Crevanille and also had a vague recollection of the angels and believed that they were not evil. Lumis wanted to take her back to Dulkheim for research. The party split up so that Vallery would take Frayne to the facility that investigated Ruin Children while the rest of the party returned to Fort Leinfaltz to finish their mission. Frayne refused to go anywhere with a stranger and wanted to stay with Crevanille, but he convinced her to go with Vallery.
While she was with the Dulkheim researchers, she refused to talk to them. Crevanille came and calmed her down. She asked why was she put asleep for a long time, leaving the world she knew, and what should she do now. Crevanille promised that they would find their goals together. She knew that they were Ruin Children but different from Vallery. When she was taken to the Ruins of Hope by the researchers, she spurt wings of blood from her back like Crevanille did.
Under Ludwig's orders, the Ruin Children from Fort Leinfaltz were secretly imprisoned for experiments. Eventually Remus rescued Crevanille and other surviving Ruin Children, and they reunited with Frayne to escape. From then on she accompanied Crevanille.
Frayne is gentle and kind and likes to observe the world due to her memory loss. She is able to read ancient language found in ruins. She wanted to help Crevanille find out the motive of the angels, and to recover her memory.
When they revisited the Ruins of Hope, Bryntir told them that he, Crevanille and Frayne are the three Angelic Children. They were engrafted with essence from the angel Uriel, created to fight against the angels. Bryntir took Frayne's angel essence to fight against Akyel. They defeated Akyel but Bryntir lost his life because invoking the angel essence was too much for a human body to bear. With the angel threat gone, the group still needed to end the war, solve the threat of summoning, and defeat Vester.
Frayne was troubled at her memory loss and felt she was lost in this world. Crevanille helped her resolve to create new memories and find a new purpose. She was inspired by the art museum at Crevanille's city and started drawing. She became a skilled artist and had her artwork displayed at the gallery.