Eagles of Manwë

The Eagles of Manwe were the messengers and spies of the High King who possessed the ability to see through most physical matter except for the deepest blackness of Morgoth's evil pits. They are possibly to be considered spirits of the Maiar who derived their abilities and shape from Manwe himself, but this is mere speculation. The limits on their sight were first discovered by Morgoth prior to the fall of the great stronghold of Utumno. Their leader and the king of these eagles was Thorondor and later descendents of his, which include the eagle lord Gwaihir, who carried Gandalf many times during the Third Age.