Phalanx Echo

The Phalanx Echo is the first boss of the Prophecy dungeon, a Taken Phalanx conjured by the Nine and summoned by the Kell Echo. It is an Ultra-rank enemy with an Arc slug rifle and shield, and is immune until players use Light and Darkness motes (from killing Taken Knights in matching zones) to deactivate the platforms. Once its shield collapses, a roughly 30 second damage phase begins. Its meaning is unclear; the Kell Echo foreshadows Eramis, while the Phalanx Echo may connect to Caiatl. It is referenced by Relentless.