Konoe Ayatsuki Mercury

Nine was a witch, and one of the Six Heroes.

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Nine was a witch and one of the Six Heroes, who taught humans to use magic during the Dark War. She is the mother of Kokonoe. During the Dark War, she created the Nox Nyctores in order to help humans fight against the Black Beast. After the war, she discovered what Terumi's future plans were, and he killed her (this action is why Kokonoe despises Terumi).

Due to similarities in their appearance and abilities, Phantom may have some connection to Nine.

It is notable that in Lambda's arcade mode, Hazama tells Kokonoe that the magical power he used to create Mu belongs to Nine.