Echo of Command
From Destinypedia, the Destiny wiki
The Echo of Command is a paracausal artifact that was released from within the Traveler following the destruction of the Witness. Like the other Echoes, it is believed to be a memory or psychic imprint of a species that was conquered and destroyed by the Witness and its Black Fleet, preserved in the Darkness and made manifest through the Light. It is currently in the possession of a version of Maya Sundaresh, who appeared on Nessus following its arrival there and used it to take control of the local Vex collective.