Soul

Souls are real in The Demonata series. They are the most prized thing to a Demonata the body will live but can't think, feel, or nothing but live. The soul can be tortured by the Demonata for eternity.

Dervish's soul was taken to fight with by Lord Loss which Dervish won so his soul came back to his body.

Without a Soul
Without a soul, your body is a lifeless shell. You are living just not showing any emotion and you can't do a lot of things by yourself. You have to be fed and dressed etc.