Hylia's Chosen Hero

The Knight of Hylia, also known as Hylia's Chosen Hero, is the title of the incarnation of Link who was chosen by the Goddess Hylia thousands of years ago prior the events of Skyward Sword.

''Skyward Sword
Not much is known about Knight of Hylia's story. However, it is heavily implied that was born on the Surface during the Era of the Goddess Hylia. It was known that Her Grace made him her chosen hero. She then gave her Sailcloth to him long ago as said in legends. The Knight of Hylia fought with the Goddess Hylia during the war against the Demon King and somehow died, leaving the Hylia the only one left to protect the world against Demise.

Skyward Sword Manga
In the Skyward Sword manga by Akira Himekawa, it is confirmed that the Knight of Hylia was a Link. Link was born on a world known as the Land of Hylia. He lived his life in a city from the world below the clouds. Link became a Knight of Hylia and was popular and respected by the Hylia people from the city and regarded as a hero. Just until one day, the hero was found imprisoned by the people of the city for 4 years, since his sword, Orville, was broken, and was decieved by Lord Dagianis, who was killed 4 years later by Demise. After his death, the peole came to free the Knight of Hylia from his prison and state that he is the only one to save the Land of Hylia from Demise's army of monsters, then give him his repaired sword and his clothes. The Knight of Hylia, Link, appears in front of many people on top of the castle, cheering up for the hero. Gazing at the sky, he says to himself that he will fight for the Goddess Hylia forever if she still needs him.

Goddess Sword/Master Sword
It is probable that Knight of Hylia was also wielding the Goddess Sword during the Era of the Goddess Hylia, until one day, the hero managed to turn it into the Master Sword as seen in the manga.