The "Shiratori" part of Amano Shiratori's name means "swan" in Japanese.
Amano Shiratori is considered a god and is used by Oorchiriou to communicate with the mortal world. Oorchiriou would only send Amano Shiratori into the human realm to protect those whose lives would change the path of fate. Amano Shiratori was first summoned forth to save the infant Osu from falling off a cliff to his death. Amano Shiratori then caught the infant and returned him to his rightful birth parents, before taking off into the night sky.
The next time Osu would see Amano Shiratori was many years later during his battle with Orochi, where the bird saved Osu and Oto from harm. Amano Shiratori flew the two into battle, but Orochi got the upper hand and cast them into the void of darkness.
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