Nothing is known of her early life but, when she is first seen, she is acting as as the Organization's eye, is sent to spy on Miria's party during the male Awakened Being incident with her handler Ermita. She senses their emotions, the tide of the battle and when Deneve is able to come back after crossing her limits. She is told by Ermita to memorize their Yoki just in case she has to cross swords with them. She comments to herself that it will be a long and arduous road to tread for the warriors to meet her.
When Clare goes missing after encountering Ophelia, Galatea is sent to search for her, and she finds Clare battling against Dauf, the former recognising her as soon as she sees her symbol. She is the first to recognise Riful's presence, easily manipulates Dauf's Yoki to avoid his attacks and manages to sever one of his hands before Riful intervened. She explained to Clare about the Abyssal Ones and then, sent her to fetch Jean while she distracted Dauf. During the battle, she released her Yoki, increasing her power dramatically, but still managed to be pierced by Dauf. When the battle is won, she attempted to bring Clare back to the Organization but, when faced with Jean, she decided to defect on the order.
Galatea became more and more suspicious of the Organization, and, although she becomes more vocal in her disobediance, they keep her due to her usefulness. She finally goes renegade during the Northern Campaign's aftermath, after the Organization show her the power of Alicia and Beth, which shocks her deeply. Before leaving, she told Rubel that the Organization's experimentations made her sick.
[edit] Seven Years Later
Galatea as a nun in Rabona.At some point, she was hunted by Dietrich but managed to escape to Rabona, where Claymores are forbidden. To be allowed into the city, she destroyed her eyes to conceal their distinctive colour and entered into the order of Rabona Cathedral as a nun, where she remained, becoming very popular with the local orphans, who saw her as a mother figure.
While in Rabona Galatea detects the presence of the awakened being Agatha with her increased sense of Yoki and uses herself as bait to get the Organization to send in members after her to help kill the awakened being. Unfortunately, the Organization only sent Clarice and Miata, whom she not only manages to sense despite them taking Yoki suppressing pills but manages to handle in battle. Miata, focusing solely on Galatea, did not notice Agatha and, during that time, she managed to sever Galatea's arm.
The three-way fight escalated until Miata and Galatea were both incapacitated. At the last moment, they were saved by Clare, Miria, Helen, Deneve, Cynthia, Tabitha and Yuma. Galatea was freed by Miria, whom she trusted with the task of defeating Agatha. Once the battle was over, she allowed Cynthia to help heal her arm and listened to Miria's explanation of the truth behind the Organization.
She is currently staying in Rabona. The priests have allowed her to stay there even though she is a Claymore. While some of the others were away, Galatea senses the activity in the South, Alicia and Beth mobilizing and Dietrich coming to Rabona. She greets her old enemy like she would a friend and, when Dietrich has left, she correctly assumes that the West is about to become a battleground.
