The series's hero and the biological son of Renton Thurston and Eureka, technically making him Ao Thurston .
His mother one day fell from a clear sky into a bay in Iwato Jima, before giving birth to Ao sometime later, who ended up in the care of his mother's only friend Toshio Fukai. Ao discovers the "RA272 Nirvash Mark One" after he unintentionally retrieves his mother's bracelet in the midst of a smuggle operation.
Ostracized by the villagers and targeted by the armies of several countries, Ao decides to join "Team Pied Piper", hoping to find her.

Source:Wikipedia