The game takes place in a reimagined late 16th century Sengoku period Japan. In it, the player takes control of a shinobi who was left for dead after his lord was kidnapped and his arm severed by a leading samurai of the Ashina clan. The shinobi awakens to find that his missing arm has been replaced with a prosthetic by a mysterious busshi who dubs him Sekiro, or "the one-armed wolf". Armed with a katana and the prosthetic, which allows for various tools and gadgets to be installed on it, he sets out to rescue his lord and get revenge

Sekiro: Shadows Die Twice is an action-adventure game played from a third-person view. Although compared to FromSoftware's Souls series, the game features no role-playing elements, such as character creation, classes, or equipment upgrades, as well as having no multiplayer elements. Rather than attacking to whittle an enemy's health points, combat in Sekiro revolves around using a katana to attack their poise and balance instead, which eventually leads to an opening that allows for a single killing blow. The game also features stealth elements, allowing players to immediately eliminate enemies if they can get in range undetected. In addition, the player character has the ability to use various tools to assist with combat and exploration, such as a grappling hook and a torch. If the player character dies, they have the option of being revived on the spot under certain conditions instead of respawning at earlier checkpoints.

Development of Sekiro began in late 2015, following the completion of Bloodborne's downloadable content, The Old Hunters. The game was revealed via a teaser trailer at The Game Awards 2017 in December, showing the tagline "Shadows Die Twice". The game's full title was revealed to be Sekiro: Shadows Die Twice during the Microsoft press conference at E3 2018. It is being directed by Hidetaka Miyazaki of the Japanese development studio FromSoftware, best known for creating the Souls series and Bloodborne, and published by the American company Activision. Sekiro's soundtrack was composed by Yuka Kitamura. The game is scheduled to be released for PlayStation 4, Windows, and Xbox One on 22 March 2019. A collectors edition of the game will also be released the same day, and will include a steelbook case, a figurine of the protagonist, an art book, a physical map of the game's world, a download code for the soundtrack, and in-game coin replicas.

Sekiro draws inspiration from the Tenchu series of stealth-action games that were partially developed and published by FromSoftware. The team initially considered developing the game as a sequel to Tenchu, but as that series had already been shaped by several different studios before they obtained the rights to it, they instead opted to take the project in a different direction. Miyazaki intended for the combat changes to capture the feel of "swords clashing", with fighters trying to create an opening to deliver the fatal strike. He and the team also created the game to be a fully single-player experience, as they believed multiplayer to have limitations they wanted to avoid. The word "Sekiro" means "one-armed wolf" in Japanese, referencing the player character's situation, while the subtitle "Shadows Die Twice" was originally only meant to be used as a slogan for the teaser trailer until Activision requested it to be kept for the final name. Despite the game taking place during the Sengoku period of real world Japanese history, there are no real historical people or locations featured in the game.