The Koroks are a species of forest creatures that are created of the Great Deku Tree on the island of Forest Haven. They are wooden-like creatures that wear leaves for masks (or that could be their actual faces), and glide around on the wind using sprouts as propellers. They may have been originally the Kokiri.
In the game The Legend Of Zelda: The Wind Waker, Link first meets them when he goes to Forest Haven to search for Farore's Pearl, only to rescue Makar who goes off into the Forbidden Woods and be captured by its boss, Kalle Demos. Later on in the game, Makar is revealed to be the Sage Of Wind when his spirit is awakened by the playing of the Wind God's Aria and helps Link in his quest to bring him to the Wind Temple on the Great Sea in order to restore power to the Master Sword.