The first thing Grey looked at wasn't blueprints or raw materials. Instead, the first thing he looked at were Spirits.
For a long while now, he had had the fang necklace hanging around his neck, and he kept meaning to find a vessel for it, but he never had.
Logically, an animal Spirit was actually quite compatible with the Mechanical Jaw Lineage. But the Mechanical Jaw Lineage happened to be the only mechs Grey had convenient access to that were worth putting Prometheus in.
There was no doubt that even beyond just the whole looping life thing, Prometheus had been a great help to Grey.
There was a moment in his battle with the Syrn where Grey felt like the pulsing of the Prometheus Spirit was helping him mimic the aspects of the alien more and actually helping him to control the black light with greater efficiency.
