The Goddess Hylia also known as Her Grace is the one entrused by the Three Golden Goddesses with the task of protecting the Golden power of the Gods also known as the Triforce. She is also known as the Goddess worshiped in Skyloft and by the Sheikah.
after the Golden Goddesses were finished creating the world, they left the Triforce in Hylia's care before their departure from the world. Eventually, a crack opened up in the earth and Demise the Demon King and his demonic hordes came out, they wanted to make the world their own by using the Triforce. Hylia entrusted the Hylian with the Triforce and sent them to the sky and created a cloud barrier to separate the Earth from the sky along with the Goddess Sword which was sealed within the Statue of the Goddess. She then do battle against Demise and his forces and sealed him within the Sealed Grounds and then gave up her immortality to be reborn as a mortal and being able to use the Triforce (Gods are not able to use it) and then entrusted Impa with the task of helping her future incarnation.