Overmind

The Overmind (サイコマスター) is the controlling intelligence of the Voxai, the leader which sends telepathic messages to the citizenry and instructs them on what to do each day. The Overmind was made up of three powerful Voxai: Leucosia (green), Ligaia (orange), and Riadne (blue). They appear to have merged their minds together, functioning as a single entity (as they are repeatedly seen to finish each others' sentences). Unlike the other tribe leaders in the Twilight Cage, the Overmind is genuinely loyal to Imperator Ix, willingly allying Sector Charybdis with the Nocturnus.

The Overmind's combined psychic powers are sufficient to take direct mental control of individual Voxai (or even Nocturnus), should they see fit. When Sonic and his friends conftonted the Overmind in Colony Alpha, the powerful Voxai attempted to control their minds in order to "free them the burden of choice". Protected by the psychic barrier of a Voxai-treated "Great Emerald", Sonic resisted. Overconfident, the Overmind freed Sonic's friends for the duration of the battle, but this ultimately lead to their destruction; Leucosia, Ligaia, and Riadne were defeated.

What remained of the Overmind's power was taken up by Thebes, who became the new Overmind.

Trivia

 * When first confronting the Overmind, Sonic isn't affected by the Overmind's power. If the player has Cream the Rabbit, Big the Cat, or Omega on their team they won't be effected either. Any other party member will be affected, uttering a brainwashed line. Shade speaks her brainwashed line whether she is in the party or not.

Etymology
The three members of the Overmind (Leucosia, Ligaia and Riadne) are named after some of the sirens of Greek mythology. Like the Overmind, the sirens could also take control of people, although they did it trough their enchanting songs rather than through telepathy.

Another named siren in some sources is Thelxiepeia, who is presumably the namesake of another Voxai, Thelxe.