Galatea, known as God-Eye Galatea, is the former Number 3 of the Organization in Clare's generation. Her background prior to becoming a Claymore is unknown, but her actions reveal a warrior of exceptional skill and eventual deep disillusionment with her creators. She is a defensive-type warrior, and her primary role for the Organization was to serve as its "Eye," a position that utilized her unparalleled ability to sense and manipulate yoki, the supernatural energy of yoma, Claymores, and awakened beings.

Galatea's personality is initially defined by a calm, haughty, and dignified demeanor that matches her high rank. She is intelligent, sharp-witted, and often uses sarcastic jibes against her enemies and even her own handlers. A notable character trait is her pronounced vanity; she takes great pride in her physical beauty and formidable power. This pride makes her reluctant to release her yoki during battle because the transformation contorts her face and body, which she considers ugly. She only unleashes her full strength when absolutely necessary, often with a sardonic remark about bearing with her "ugly face".

Her motivations evolve significantly throughout the story. Initially, she appears to be a loyal operative, but she gradually becomes more suspicious of the Organization's motives and experiments. She finally abandons the Organization after witnessing the power of Alicia and Beth, the Organization's attempt at creating controllable awakened beings, an act she finds sickening. Following her desertion, she seeks refuge in the holy city of Rabona, where Claymores are forbidden. To gain entry, she gouges out her own eyes to conceal their distinctive silver color, a drastic act that demonstrates her commitment to escaping her past. She then reinvents herself as Sister Latea, a blind nun who devotes herself to caring for the city's orphans. In this role, a more nurturing and maternal aspect of her personality emerges, and she develops a fierce sense of responsibility to protect the city that became her home.

Her relationships with other characters are key to her development. She shares a complex bond with Clare, the series' protagonist. Initially, she mocks Clare's low rank and abilities but later regards her with great interest, particularly after witnessing Clare's ability to push past her limits and return from the brink of awakening. They eventually greet each other as old friends. She also holds a significant relationship with her handler, Ermita, whom she treats with little respect, often challenging his orders with her characteristic wit. After her desertion, she was pursued by the warrior Dietrich, but when they meet years later, Galatea greets her former enemy with a pleasant and charming, if ironic, hospitality.

In the story, Galatea is a pivotal figure. She is sent to retrieve Clare after she goes missing, which leads to a major confrontation with the awakened being Dauf and the Abyssal One, Riful. During this battle, Galatea demonstrates her incredible abilities, holding off Dauf to allow Clare to save the warrior Jean. Although her mission was to bring Clare back, she ultimately chooses to let her go, reporting that they both died. After the seven-year time skip, her role shifts from active warrior to tactical ally. Living in Rabona, she becomes aware of the awakened being Agatha hiding in the city. Unable to fight as she once did, she uses herself as bait to lure the Organization into sending warriors who could help kill the creature, leading to a reunion with Clare and her friends.

Galatea's most notable abilities revolve around her mastery of yoki perception. Her power earned her the title "God-Eye Galatea". Her abilities are two-fold. First, she has unparalleled yoki sensing, capable of detecting the energy of other warriors and awakened beings from immense distances, reading their emotions, and perceiving their actions as if she were beside them. After losing her sight, this sense sharpened to the point where her blindness is no handicap. Second, she is a master of yoki manipulation. She can subtly interfere with the yoki flow of her opponents, allowing her to alter the trajectory of their attacks, control their movements, and even forcibly push a Claymore past their limits or pull them back from awakening. The physical strength she gains from releasing her own yoki is among the highest of all warriors in her generation. Despite her power, she is not invincible; her intense focus on maintaining her beauty means she is slow to use her full strength, a flaw that has been exploited in battle.