When
Zidane awakens on the Hill of Despair, he is greeted by Necron's voice emanating from rays of light above the hill. The entity announces that by observing
Kuja's murderous actions it has come to the conclusion that all life exists merely to seek death. Necron resolves to destroy the
Crystal, the origin of life, and thus revert everything to a "Zero World" of perpetual nothingness. It teleports the heroes to a coliseum-like structure and engages them in battle.
Though Necron utilizes a plethora of destructive magic, it is ultimately defeated. Kuja uses the last of his powers to teleport Zidane and his friends back to the
Iifa Tree, and as Necron dissipates, it is shocked to find the power of the will to live is so strong. Nevertheless, the being pledges that it will always exist, as long as there is life and death.
In "Final Fantasy 20th Anniversary Ultimania - File 1: Character Book", Necron is described as, "a being awakened by Kuja's fear, despair, and hatred, which called out to it as he learned of his mortality, just as his ambitions were within reach".