Prologue
After a year of wandering alone in the world, the last mortal alive still hold into hope while running from the monsters that come out of the dungeon after the One-Eyed Black Dragon destroyed what is left of Orario after the war game the Freya Familia to claim the boy has indeed with an unimaginable ending with him killing off the entire Freya Familia with a way that would make most monsters terrified.
Most of them were burned like they were burned by hellfire, most of what is left were either dead by blood loss from losing their arms, legs, or both or from having their internal organs crushed inside of them or removed from their bodies as for their most powerful members they were cut to pieces like they were nothing but meat except for two one was spared suffering by being knocked out by one punch but the last one suffered a fate worse than all the others for he was cut down burned broken body part organs spread only to be healed again and again for an entire three days without second of rest even when he was getting healed because the healing was made so that the person suffers and his last words were "I wish you never found us".
That was the beginning of the end.
The boy escaped the monsters and killed the one he needed to complete the artifact that will help him prevent the end of everything but he had to make sure he would not be sensed by anything or anyone. He needed only to believe. He had given that artifact the name of the person that enables him to get this far and give up her existence to give him the power to survive to save the world. The artifact was called "Aiz's bell of hope".
When he activated it he begs if doesn't work that his soul is to be destroyed. The boy Bell Cranel or as his last alias "Mercenary Devil" is trying to save the world by stopping the Goddess of (false) Beauty even if he has to become "Devil" again.