When Cooro is first introduced, he is a wandering child on the prowl for other +Anima. The audience is left with little to envision at this point. Perhaps he was an orphan running away from home and looking for a family? Perhaps he was raised by birds in the wild? What could possibly be the backstory behind Cooro? What makes him so different from other +Anima?

There is a reason Cooro cannot remember ever being a normal human, it was because he was always a +Anima. However, though most people believe that he was born that way, he was not. At least, he was not born that way in a traditional sense. No human in this land could be birthed in the traditional sense and be a +Anima.

"What I witnessed was the funeral of a young mother who died while still with child. The deceased's spirit is taken to heaven by the crows. It must have been no different with the soul of this mother." - Dr. Eiron Newt (ch56)
Cooro's mother had died in mid-childbirth. (She was either giving birth in the field or someone had thrown her body there, that is not explained.) While her carcass was being torn apart by hungry crows, her baby boy was alive and struggling to survive. The crows had given Cooro his +Anima spirit, and since no one human recalls being born or the events of those early moments, Cooro had assumed that he was born +Anima.

Cooro, as a new born infant, was able to fly away from the scene, only for a short length of time. He soon came crashing in through the ceiling of a local church. It was known as the day that an angel with black wings had fallen to the earth. It was later when Cooro was influenced by Fly Greena, an apprentice of Eiron Newt, and given him both his mission and tried to take away his freedom.