The Melody of Oblivion

A girl whose physical body is confined at an elusive area called the "Oblivion Playhouse" (also translated as "Melody Theatre,") but can project her image so that Meros Warriors can see her. She guides and supports them, although her capacity for communication seems to be very limited. It is rumored among Meros Warriors that if her physical form can be located and resuscitated, she could unlock a power capable of wiping the Monsters off the face of the planet.

Souce: Wikipedia