The notion that when you die only the body is left to be buried is a worldwide accepted truth, but what happens to the soul or a person’s essence from the moment someone passes on. Their essence is left behind in a transitional state. One that binds them in the in-between of two worlds. The light side of Empyrean and the dark side of Hades. Only until they cross over are they truly gone, so in the meantime they are here and the walk-ins can interact with them and see them and work together with either side of the war.
These souls are pivotal to tip the balance.