The Prize Of A Soul is a quest of Necropolis playthrough in Might & Magic: Heroes Online.
The head of soul hunters explains when they have a contract, the soul of the living is bound immediately to the collector, which could turn the soul into an eternal ghost. Thus, Yorath and the hero have to confront the soul collector, who is already conducting the ritual to bind the soul. Yorath stands with the hero, as both of them have to defeat the soul collector's lost souls. Once done, the soul collector promises to give away the soul if they don't harm him. The hero has to report to the head of soul hunters, who gives the key for the cage.