Since childhood Sara has been groomed to become Mayan Island's priestess/shaman, a position of great spiritual importance to the people of the secluded island. It also means having the "mystical power" of interacting with the island's mysterious alien ruins, a little-understood ability that she manifests through singing an ancient Mayan chant. She also gets occasional visions into the future. This power seems to run through her family's blood as her little sister Mao also displays the same abilities to a lesser degree.

As a child she agreed to let a visiting scientist test her blood (an act forbidden by the island's traditions) in exchange for a pretty bauble. The test confirmed her special properties and would later make the island's inhabitants the focus of research and then armed conflict. Due to this incident Sara has grown up suspicious of outsiders and very protective of her people's beliefs. She resents the wind of change that the abrupt arrival of U.N. pilot Shin Kudo brings to her home, yet she realizes how powerless she is against it as she foresees the destruction and violence that is to come.