Hylia

Hylia, also known as Her Grace, is a goddess mentioned in Skyward Sword.

History
When the gods of old departed from the world, they trusted their ultimate power in the hands of Her Grace to protect it. However, one day, evil creatures rushed forth from the depths of the earth and launched an attack against the people of the surface, murdering them and causing misfortunes all just to get their hands in the power guarded by Hylia.

To prevent the great power from falling into the hands of the demonic creatures, Her Grace gathered the surviving humans on a piece of land and sent it to the heavens, beyond the clouds and out of reach from the evil plaguing the land. Now that the humans were safe, the goddess and the five tribes who lived in the surface joined forces and sealed away the evil forces, restoring peace to the land.

Hylia appears in the opening alongside the five surface-dwelling races; from left to right, the Ancient Robots, the Parella, the Kikwis, the Gorons and the Mogmas.

Theory

 * Hylia's primary antagonist, the Demon King Demise, possesses a sword that seems strikingly similar to the Master Sword. It remains unexplained whether the blade wielded by Her Grace and her chosen hero was specifically created to counteract Demise's weapon or vice versa. This is made further unclear by the fact that Fi and Ghirahim are similar humanoid beings accompanying each sword.