The narrator is revealed to be a Lufenian scientist named Cid who traded his body as part of a deal with Shinryu. The Warrior of Light is a manikin based on Cid while Cosmos is a manikin based on Cid's wife. While Cosmos is technically not a Lufenian, being modeled after Cid's wife means she may represent what a Lufenian looked like during Cid's time. Spoilers end here.