The realm Haven is a dark dimension of memories that would later be known as the Underworld. It was secretly built by a group of Slayers led by Charon with the permission of the Archduke Azrael. They hoped that Haven could be a safe place from the Angelic Host where the souls of dead mortals could be kept and live comfortably while the war against Heaven continued. Building this new realm between Creation and the Second World, they hid it from others with a Veil of pain and suffering that made it impossible to be seen from the land of the living, but allowed those within to watch Creation.