Callisto is a servant of Artemis and commander of the Satellites, the personal guard of Artemis.
As Commander of the Satellites and right arm of Artemis, she is very close to the goddess. She ordered Lascoumoune to kill Athena and Shun without Artemis adknowledging to prevent her from suffering for the choices of her sister, and free lunar Toma, the fallen angel, and sent him to kill Seiya.
She dons silver armor and possesses a scepter crescent-shaped staff, similar to that of Artemis. Her name is derived from the nymph Callisto, who according to mythology was part of the result of the goddess of the hunt of which she was a lover, and it is likely that they are the same thing.