No.
Neither, actually
"Heaven's grant" does not refer to a materia and the Comet materia is not referred to. Your speculation was good, but the riddle is a bit more literate, mostly. Only one line in the riddle is fully metaphorical.
It's not the Position Marker.






Kudos to starseeker for the sig \m/
Do u play rs(runescape)if u do pm me!!!





