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The Harbinger Minds, or Harbingers, are "trophies from an ageless war" kept by the Awoken and used as superweapons. They have some degree of intelligence: they would react to speech and may be communicated with. The Harbingers are under the control of the Techeuns and the Queen of the Reef, though it seems that this control may be tenuous. As weapons, they had little finesse and had the potential to cause enormous collateral damage; as a result, they could not be deployed near allied forces or civilian populations. Their use as weapons may be gravitic in nature; during the Battle of Saturn, asteroids and Tombships were drawn in after their trails.
The first known use of the Harbingers was when the Queen "awoke" them for the opening salvo of the Reef Wars, destroying Ceres and half of the Wolf fleet stationed there, including their Kell, Virixas. During the Siege of Pallas the Queen was reluctant to use them, as doing so would have destroyed both the defending Awoken fleet and killed the entirety of its civilian population. Instead, a Reef-manufactured illusion of their presence broke the siege, scattering the dismayed Fallen.
The Harbingers were last deployed against Oryx's fleet at the Battle of Saturn. This was in accordance with a plan that "overcame death and spanned universes" devised by the Queen, in which all but the eldest Harbinger would be sent against the Dreadnaught to burrow into its hull and "have children." On summoning, they devastated many Hive warships and Tombships, but apparently failed to harm the Dreadnaught. Oryx, the Taken King then activated the Dreadnaught's main weapon and destroyed the Awoken fleet. Uldren believed the Queen and the Coven had overstepped themselves in challenging Oryx's power, as it was "not bound to anything the Origin Libraries even sought to describe". In truth, the Harbingers had done exactly as the Queen planned, and allowed her to enter Oryx's throne world when his weapon killed her.
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