Indentured Protector

Indentured Protectors are human ghosts found at the Obelisk of the Stars in Uldum.

They can only be seen using Sapphire Spectacles, which you get while doing the quest By the Light of the Stars. Once the player loots Suspended Starlight, any protectors nearby will become hostile and attack.

Speculation
They may have originally been a part of the Wastewanders.