Maduin and Madonna
Maduin and Madonna are Terra's parents. One day Madonna wandered through the sealed gate and met Maduin. They decided to see if a bond between a human and an Esper could exist. With Maddona being a female human, and Maduin being a male Esper, this made Terra into a half-human, half-Esper being. Two years after Terra was born, the empire stormed through the sealed gate. They captured some Espers along with Maduin and killed Madonna. Terra was taken by the Empire.
