Florette Harvenheit

Fiore, a girl with a mysterious past, is Joshua’s guardian, who is very protective of him. She is a powerful jewel summoner and has a very special role in Aion’s group. She is also an excellent cook, and a very capable maid who likes to take care of everybody around her. She has been looking after Joshua since he first joined the Sinner group, when he was still a boy. Though she appears to be cold and almost emotionless, she’s actually a very sweet and caring girl, though she is also a fearless fighter. Joshua and her share mutual feelings that go beyond sibling love.

However, it was later revealed that she was also a jewel summoner, like Satella, and that she was Satella's missing sister Florette. She had been kidnapped by Aion and her personality replaced by "Fiore", so that she does not remember that she is Satella's sister. In her final battle with Satella, she ruthlessly attacks her sister and only at the end did she remember Satella as she was killed.