Demon’s Souls is set in Boletaria, a kingdom consumed by a dark being called the Old One following its release through the use of forbidden Soul Arts. Players take on the role of a hero brought to Boletaria to kill its fallen king Allant and pacify the Old One. Gameplay has players navigating five different worlds from a hub called the Nexus, with a heavy emphasis on challenging combat and mechanics surrounding player death and respawning. Online multiplayer allows both player cooperation and world invasions featuring player versus player combat.

The world is divided into six areas; the Nexus hub world and five additional worlds subdivided into four areas which each end in a boss encounter. Combat is reliant on timing for weapon strikes and blocks, with different weapon types opening up a variety of combat options and altering the player’s movement speed. Most actions drain a stamina meter, with its management forming a core part of combat.