Watcher

A Watcher is an enemy featured in Skyward Sword. They, along with the Guardians, protect and patrol the Silent Realm. However, unlike the Silent Realm Guardians, the Watchers are not affected by the Sacred Tears and thus will not be stunned by its power.

The Watchers shine a light through the realm. If Link passes through this light, the Watcher will emit a loud sound that will awaken the Silent Realm Guardians, canceling the effects of the Sacred Tears, no matter how much time Link has remaining.

There are two types of Watchers. The Sky Watchers patrol the air with a light in a fixed route. The Earth Watchers hover near the ground, and will chase Link if he gets too close to them. However, he can outrun them by dashing. Earth Watchers give away their position in ways that give Link warning so he is not caught off guard. A visual cue is that the Watchers have dimmer, larger light radii, and it is safe for Link to be caught in this light, as long as their brighter direct light does not touch him. They also have a sound cue, as Earth Watchers will give off a jingling sound upon noticing Link.

Trivia

 * Watchers bear resemblance to Poes and the Poe Collector from Ocarina of Time. The lanterns they hold increase the resemblance.