Story-wise, Demon's Souls tells of a flourishing medieval kingdom which transcended into chaos because its king had accidentally awakened an ancient power, causing the kingdom to be enshrouded by a strange fog. As no one ever made it out of the fog, the outside world remained oblivious as to what really happened… or whether the population trapped within were still alive, for that matter.
One day, a survivor emerged from the fog and told the outside world of demons rampaging the kingdom, and that people trapped inside were either dying or going mad. And with the fog slowly spreading its way across the land, other heroes began making their ways into the fog in a desperate attempt to find the cause of the phenomenon and stop it before it was too late. 5/5