In The Legend of Zelda: Tears of the Kingdom, there are 4 Great Fairies. After you complete their quests, you’ll be able to enhance your armor. It will cost you 10 rupees plus the materials. Below are the locations of these 4 Great Fairies!
Great Fairy Cotera
The Great Fairy Fountain for Great Fairy Cotera can be found along the river just south of the Twin Bridge.
Great Fairy Kaysa
The Great Fairy Fountain for Kaysa can be found northeast of Nephra Hill.
Great Fairy Mija
The Great Fairy Mija’s Great Fairy Fountain can be found in the Tabantha Tundra northeast of the Snowfield Stable.
Great Fairy Tera
The Great Fairy Tera’s Great Fairy Fountain can be found north of the Woodland Stable, which is northeast of Central Hyrule.