True Demon

The Gravemind was a thousand billion minds. When Halo wiped out the vast majority of it, a small core, a Keymind, was safely ensconced in its own private pocket of space. Yet They were not alone there. There was a reason that the Gravemind never referred to John-117 as Demon. He could never match up to the horror and power of the real thing... Metroid. Oneshot, spoilers.