Not all the Sinners suffer in Hell eternally. Some of them take advantage of infernal guards' negligence and run away. The wicked hide in the Purgatory, and try to get to Heaven under the guise of the Blessed which is strictly forbidden according to the underworld laws. It is not politically correct.
Only you can stop them and bring the deserters back. You fear neither terrible creatures, nor Purgatory dangers, nor Almighty apostles. Your weapons are scythes and magic. Your mission is to collect souls. You are the task force of Hell. You do the ultimate job.