Hero in Black

Bell Cranel, a young boy with a heroic dream. Wanting to become like the hero in the fairy tale he read. He try hard everyday, to become a hero figure like the one he admire... But one day, he go into the dungeon alone and never return. Everyone including the Hestia Familia try to find him for months but found nothing... Until 2 years later, an enormous power produce from deep under the Dungeon... And the boy return, with a blade that can slide the world.