Theosyion, the Restorative Mind

"Restorative Minds are of the Weavers, carrying the means to undo any Mind's undoing."

- Ikora Rey

Theosyion, the Restorative Mind is a Vex Axis Mind Harpy encountered in the Echo Chamber Strike. Restorative Minds like Theosyion are deployed when a significant node of the Vex network shuts down; in Theosyion's case, its purpose is to bring an intact Sekrion, Nexus Mind into the present from the past in order to restore the network and resume the transformation of Venus into a Vex machine.

Gameplay
Theosyion is normally totally immune to damage, and rapidly fires dual Arc Harpy Slap Rifles at any nearby enemies. The only way to make Theosyion vulnerable to attack is by using Arc sources to short out various Vex installations. This forces the Harpy to lower its defenses and move towards the next position. It also has an additional attack called Medusa's Gaze; any enemy caught within its line of sight will be killed instantly. If someone is being targeted by Medusa's Gaze, they need to break line of sight immediately.

Trivia

 * Theoysion is the only known Vex enemy to not belong to any current faction, not even being labeled as a Precursor or Descendant. Lorewise, this could mean that newer, more advanced machines from hitherto unknown times are coming to reinforce the Vex, as Variks observed, now that they recognize the Guardians as a threat.
 * Theosyion is so far the only Vex enemy that deals Arc damage.
 * Theosyion is the only Harpy boss to appear in Destiny even with the Curse of Osiris expansion.

List of appearances

 * Destiny
 * The Taken King