When Bahamut was defeated by Phoenix Louisoix, crystallized shards of Bahamut's disintegrating form skewered several parts of Eorzea, including the Pharos Sirius. What exactly is this orange "corrupted aether" supposed to be? I didn't understand what it is exactly.

Also, the crystals spawned some "Corrupted Sprites" that used light-elemental magic. And now in the hard mode, they apparently evolved into Ghrah, disc clusters that can arrange into certain shapes. I wonder if other elementals can evolve into aspected Ghrah.