The sun watched Terra, always shining down upon the earth and those who live on it and work it, providing light and warmth for the people it watched. It's always been watching, ever since the dawn of time. It saw the birth of all civilizations: Humanity, the Dwarves, the Sarpa, and so many more. It has seen civilizations prosper, and then decline, only ruins and monuments being left behind. It saw the birth of the Church in Navea, saw the birth and deeds of Reinhardt, and saw the illness of Suna.
The sun admired all that Reinhardt had done, and had silently, and secretly, grieved when Suna fell ill. It watched as Reinhardt once more donned his armor in the search of a cure, and had grieved once more when he came back empty-handed and heartbroken; and then watched as he disappeared off to where not even it could find him. Then, it watched as pirates and bandits threatened the people it watched over, as hostile creatures came forth to ravage the people, and as monsters and evil ghosts arrived on the edge of civilization.
The sun had seen similar happenings throughout all the time it has been watching, and though it may grieve for its people, it would only allow itself to silently stand by and continue to watch, no matter how long it grieved. But then, one day as it still watched over its people, it caught sight of a black-armored knight treading upon the earth, demons and destruction following wherever he went. Never before had the sun seen such darkness intruding upon Terra, and it knew that it could not just idly stand by like all the other times it had done so.
As the Power of Gaia worked once more, awakening spiritual gifts in certain individuals, the sun did what it could. It called forth a spirit, in the form of a knight, from the heavenly realm of Aura Kingdom, giving this spirit the name Aelius. The sun gave Aelius its crest, enabling him to use its own power of light and heat. Then, when all was ready, the sun sent Aelius down to Terra, to find an Envoy of Gaia to fight alongside with, so that together, Eidolon and Envoy could end the darkness that threatened to engulf Terra.
Donned in armor and his face hidden by a hood, Aelius arrived onto Terra, setting his feet upon the earth that the sun had always watched. He knew his mission, to protect and serve; to end the darkness. But first, he had to find an Envoy, someone to fight alongside with so they could both use their maximum potential. So, wielding the powers of light and heat, and emblazoned with the sun's crest, Aelius set one foot in front of the other as he began walking, beginning his search for his Envoy as the sun continued to watch on.