What would one call something that watches over people and holds the fate of the world in its hands?
im writing yet another story. the idea is there is this thing (it looks like a normal person, but floats around and glows and stuff), it is rumored to hold the fate of the world (if all of them are killed, then the world will be plunged into darkness, etc). there is only one of these things left, people tie their souls to it to help it build power and it is controlled by a single person. however, this person has to have a very pure heart.
what would a creature like this be called? i need some ideas.