Have you heard the legend of the "Folk Shadow"? They are the Sheikah ... The shadows of the Hylians. They say they swore allegiance to the King of Hyrule and protect the Royal Family ...
-Shikashi
The Sheikah, also known as Folk Shadow, are a recurring race in the saga of The Legend of Zelda. They are an ancient clan of ninjas, warriors who have sworn to protect the Royal Family of Hyrule, even after death. That is why they came to be known as "the shadow of the Hylians." They were experts in magical and combative art. It is assumed that many died during the Civil War of Hyrule and are considered almost extinct in the events of The Legend of Zelda: Ocarina of Time.
Before The Legend of Zelda: Breath of the Wild, there were only three known Sheikahs that appear in the games, although only one of them was confirmed by Nintendo. To maintain the mystery, its emblem makes many small appearances in several games of the saga.
