Valoo is a character from The Wind Waker. He is the almighty Sky Spirit who resides at the top of Dragon Roost Mountain and protects the Rito people that dwell on Dragon Roost Island. When the time comes, he grants children of the Rito people their wings by giving them one of his scales. Valoo speaks the ancient Hylian Language, and only Prince Komali's Grandmother could fully understand him prior to her death. Even Medli, his attendant during the events of The Wind Waker, has trouble understanding him.
Prior to the the events of The Wind Waker, Valoo's attendant was Prince Komali's Grandmother. She would look after him, but she died in a way unknown to Link.
When Link first visits Dragon Roost Island, he learns that Valoo is in a fit of rage. After Link climbs to the summit of Dragon Roost Mountain, Medli concludes that something is harassing the great dragon. In fact, he is being tortured by the tremendous monster, Gohma, hidden within the mountain, beneath Valoo's high peak. Link must defeat Gohma in order to obtain Din's Pearl from Prince Komali.