Watcher

The Watchers are a type of ghostly creature guarding the supernatural reality known as the Silent Realm. Like the Silent Realm itself, the Watchers are creations of the Goddess Hylia tasked with patroling the realm in search of desincarnated spirit of the hero who would eventually wander into the Silent Realm in search of relics left behind by the Goddess.

Behavior
There exist two types of Watchers, the low altitude ones and the flying ones. Unlike the Earth Guardians and the Sky Guardians, the Watchers are not affected by the Sacred Tears and will wander through the Silent Realm no matter what. They do not hunt Link like the Guardians and patrol on a set path instead. The Watchers carry a sort of lamp with them that will project a light around them. If Link enter this light, the Guardians will be awoken until another Sacred Tear is found. The flying Watchers are relatively passive but the ones at Link's level will try to chase Link if he enter their field of vision. The Watchers cannot hurt Link and he cannot hurt them.

Trivia

 * Watchers have are very similar in appearance to certain incarnations of the Poe, a reccuring Zelda enemy.