Who is the Warrior of Light?
The common answer would be the nameless heroes of the original Final Fantasy, the Heroes of Light who struck down Garland, his four fiends, the almighty evil of Chaos, and closer of the eternal time loop that resurrected Garland.
However...
That is merely a small part of the Warrior of Light's identity, and the character I speak of today is not one of the four heroes of Final Fantasy, but rather the original character created for Dissidia Final Fantasy. Later on his life, he would travel to the world of Final Fantasy and begin his adventure there, but before that, his story begins in Dissidia.
The Warrior of Light was not born as a man, but rather is a manikin created from Cid of the Lufaine. Soulless and without purpose, he was placed into "World B," a world of conflict, one between Cosmos, the goddess of harmony, and Chaos, the god of discord. Unlike his peers, he was not drawn into this world, rather he originated from it. This world's war however does not have an end however; after a victor is decided, the dragon Shinryu takes everyone's memories for himself and restores the dead, effectively continuing a cycle of perpetual violence. The nameless warrior is taken to Cosmos and she in turn bestowed him with power in exchange for becoming her champion. As a champion of Cosmos, he battles through a eleven cycles of warfare, though it would always end in her defeat.
During the twelfth cycle, the war once again favored Chaos's, this time thanks to an army of manikins, an unending spring of military might. The Warrior of Light, realizing that this war was unwinnable, turned his blade against his own allies, putting them to sleep for the next cycle. He had realized the reality of his cyclical world and accepted defeat preemptively knowing that the next cycle would possibly grant him the opportunity to succeed and end the cycle. His onslaught leaves Cosmos's forces crippled to only a few warriors. Said survivors dedicate themselves to stopping the flood of manikins and closing the rift from which they appear. They succeed though at the cost of their lives, exhausted to the point they cannot return to the next cycle. The Warrior of Light stays behind to protect Cosmos from the manikin army, though she sacrifices herself to save him. After her defeat, Shinryu once again takes his soul to renew the cycle, though this time now with a chance to end it once and for all.
In the thirteenth cycle, Cosmos tasks him with finding one of many crystals that may defeat Chaos and end the conflict. After cutting through Chaos's forces he faces Garland who tells him the cycle from which they are trapped. They duel and the Warrior prevails, gaining his crystal. He returns to Cosmos with the rest of the champions who each have their own crystals, however Chaos teleports everyone into his realm. With Cosmos in the palm of his hand, he incinerates her, killing her once again. However, the heroes of light do not fade. Unbenownst to them, Cosmos had imbued the crystals with every last bit of her light, making it so that she could not be revived, but the heroes would remain. Thus, the cycle had ended, with Chaos as the ultimate victor and his will was the complete destruction of the universe, leaving only chaotic nothingness behind. Cosmos's remaining forces were determined to end the destiny they were given. With the crystals, they open a portal to Chaos's Shrine and slay him, putting a definitive end to the world's conflict.
Shinryu, with no memories to feed on anymore, returns everyone to World A, the original world where Cid of Lufaine originated. Then, each of the heroes returns to their own timelines- everyone, except for the Warrior of Light. With nowhere to go, he walks forward to a castle in the distance, setting the stage for the original Final Fantasy, where he would fight Garland, save the princess, defeat the fiends, and end yet another time-loop.