Dark Souls is a 2011 dark fantasy action role-playing game developed by FromSoftware and published by Namco Bandai Games. A spiritual successor to FromSoftware's Demon's Souls, the game is the first in the Dark Souls series. The game takes place in the kingdom of Lordran, where players assume the role of a cursed undead character who escapes from the Northern Undead Asylum and begins a pilgrimage to discover the fate of their kind. A port for Windows featuring additional content, known as the Prepare to Die Edition, was released in August 2012. It was also released for consoles under the subtitle Artorias of the Abyss in October 2012.

Dark Souls has been cited as one of the greatest video games ever made. Critics praised the depth of its combat, intricate level design, and use of flavor text. However, they were divided on the game's unforgiving difficulty. The original Windows version of the game was less well-received, with criticism directed at several technical issues. By April 2013, the game had sold over two million copies worldwide. Its success led to the development of two sequels—Dark Souls II (2014) and Dark Souls III (2016)—while a remastered version was released in 2018.

Dark Souls is a third-person action role-playing game. A core mechanic of the game is exploration. Players are encouraged to proceed with caution, learn from past mistakes, or find alternative areas to explore. Dark Souls takes place in a large and continuous, interconnected environment, connected through a central hub area. The player character can travel between areas and explore various paths at will, although prerequisites must be met to unlock certain areas.

A central element to the gameplay of Dark Souls is the bonfire. Bonfires are scattered throughout the world and serve as checkpoints. By resting at a bonfire, the player character is healed to full and regains all of the healing charges of their "Estus Flask." They can also level up and perform other functions, such as attuning magic and repairing and upgrading equipment. However, resting at a bonfire respawns all of the world's enemies, except for bosses, mini-bosses, and killed non-playable characters.

The player character's interaction with the world of Dark Souls includes a great deal of combat. Combat includes melee attacks, ranged attacks, various forms of defensive maneuvering, and magical abilities. For melee attacks, player characters have access to a wide array of high fantasy, medieval-style weaponry—including swords, spears, maces, and fantastical weaponry such as magical swords, huge greatswords, and immense clubs. For ranged attacks, player characters have access to an array of bows and crossbows. For defence, player characters have access to shields, armour, dodge rolling, backstepping, and parrying. For magic, which includes a wide variety of offensive and defensive abilities known as sorceries, miracles, and pyromancies, player characters do not use any form of mana as in most other fantasy RPGs. Instead, they gain a discrete number of uses for each attuned spell when resting at a bonfire. These various forms of combat all have tradeoffs, variations, and in-game costs associated with them. They can all be buffed or altered in some fashion through levelling, smithing, consumable items, magical rings, and new equipment.

Another aspect of Dark Souls is the "humanity" system. There are two forms the player character can be in during the game, human form or undead form. Whenever the player character dies in human form, they are returned to undead form and can only return to human by consuming the humanity item and issuing the command at the bonfire to restore humanity. While in human form, the player character may summon other players and non-player characters (NPCs) to assist them, but they may also be subjected to invasions by other players and NPCs who seek to kill the player to restore their humanity, harvest souls, or achieve some other goal. Humanity can be acquired in many ways, and if no humanity is available, players can still progress in undead form. Death results in the loss of all carried souls and humanity, but players revive as undead at their most recent bonfire with one chance at returning to where they died to recover all lost souls and humanity. If the player dies before reaching their "bloodstain," their previously accrued souls and humanity are permanently lost. Carrying humanity grants bonuses and resistances, incentivizing players to hold onto their humanity.

Communication and interaction between players are deliberately restricted. Outside of some character gestures, the only communication players have with one another comes through orange soapstones, which allow players to write preset phrases that others can read in the same area. Also, players can enter cooperative or player versus player combat with each other. Throughout the game, there are multiple NPCs that the player may encounter on their journey. These characters add to the plot of the game but are not essential. If the player chooses to engage with them, some of the characters can assist the player by being summoned for certain boss fights when the player character is in human form.

The multiplayer component for the PC version of Dark Souls was disabled in February 2022, in response to a security threat within the matchmaking system found that same month. In October 2022, Namco Bandai confirmed that online multiplayer for the "Prepare to Die" version of the game had been permanently disabled due to aging hardware, but noted that they were working on restoring online multiplayer for the Remastered version.