Metis

Metis a heroine from Persona 3: FES.

Appearance
Metis is humanoid android and the same model as Aigis. She has a golden helm-like headpiece with a red butterfly visor. Her skin is pale, she has black hair and red eyes. As an android, her body is mostly mechanical, her armored body is black, though her right arm is white. She has a metallic "skirt" which continues the red butterfly motif.

Personality
Metis has a child-like personality and cares deeply about Aigis, whom she recognizes as her "sister", and as a result tries to protect her from harm. Initially, Metis is hostile toward the other S.E.E.S. members, claiming that they're the reason for the time skips and attempts to eliminate them. However, once she's subdued and everyone has had a chance to interact with her, she's accepted into S.E.E.S. and begins to cooperate with them to find the reason for the time skips and the reappearance of the Abyss of Time. Once everyone begins fighting for the keys, Metis sides with Aigis and claims that she was created to facilitate the fighting, returning to her previous hostility toward the rest of S.E.E.S., but at the cost of Aigis's trust.

Trivia

 * As mentioned in Persona 3's drama CDs, Metis' face is based on the face of a hospitalized girl Aigis once met. This girl may possibly be the one in Labrys' memories, whose personality served as the basis of the personalities of the early Anti-Shadow Weapons.
 * Her name, like Aigis, comes from Greek mythology. Metis (Μῆτις, "wisdom," "skill," or "craft") is sometimes presented as lover of Zeus and mother of Athena, which may refer to Aigis' ultimate Persona.
 * Metis' version of Orgia Mode not only improves her offensive capabilities, but also allows Metis to perform attacks for free.
 * Descriptions of Metis' true nature implies that she may actually be Aigis' Shadow. Towards the end of the game, Aigis refers to Metis as the embodiment of her repressed emotions and desires, which fits the description of a Shadow Self. She also accepts Metis as part of herself in a similar fashion to those of the characters of Persona 4 shortly afterwards.
 * Also, during the scene where SEES witnesses Aigis' past in Empyrean, Metis can be seen emerging from Aigis' shadow, after stating that she wishes to discard her emotions in order to escape the pain of losing the Protagonist.
 * In Persona 4: The Golden, Margaret states that Marie is an entity that belongs to the "other side", which is also where Metis says she belongs in. It is said to be inhabited only by Shadows, supernatural deities such as Nyx, Izanami and Erebus, and the residents of the Velvet Room such as Elizabeth, Margaret and Igor. Unlike Marie, however, who was actually an avatar of Izanami, Metis is not believed to be a deity or an avatar of one nor is she a resident of the Velvet Room, therefore further hinting her true identity as a Shadow.