Nioh is a single-player action role-playing game. The story follows William, a foreign warrior drawn to Japan in the early 1600s. Arriving during the turmoil of the Sengoku period, William becomes entangled in conflicts involving warring clans and supernatural beings known as yokai. Guided by his search for an alchemist who has stolen his guardian spirit, William journeys across battlefields and villages, facing both historical warlords and mythical threats. The narrative blends elements of real history with folklore, presenting the player as an outsider navigating a war-torn land filled with both human rivals and otherworldly forces.

Gameplay centers on fast-paced melee combat with an emphasis on precision, timing, and resource management. William wields a variety of weapons including swords, spears, axes, and kusarigama, each offering distinct attack patterns. Stances provide tactical variation: high stance delivers powerful but slower strikes, mid stance balances offense and defense, and low stance favors speed and evasion. Combat requires careful use of Ki, the game’s stamina system, which governs attacking, blocking, and dodging. A technique called Ki Pulse allows players to recover stamina quickly if timed correctly.

Enemy encounters range from human samurai and bandits to supernatural yokai, each demanding different approaches. Yokai can create zones of corrupted energy that hinder stamina recovery, requiring players to adapt and counter with well-timed Ki Pulses. Boss battles serve as major challenges, testing mastery of weapon skills, stamina control, and enemy study. Defeating foes rewards experience points known as Amrita, which are spent to increase William’s stats across categories like strength, dexterity, and magic.

Progression is further shaped through loot and equipment. Enemies drop weapons and armor with randomized properties. Forging and enhancing gear at blacksmiths allows refinement of weapon attributes and special effects. Guardian spirits, which represent mythological creatures, grant passive bonuses and powerful living weapon abilities when summoned, temporarily enhancing damage output and resilience. Skill points gained through combat unlock weapon techniques, magic spells, and ninja tools. Shrines are scattered across levels allow players to save progress, level up, and manage guardian spirits. At shrines, players can also interact with Kodama, small guiding spirits that provide bonuses when rescued.

Online features include summoning AI-controlled revenants of other fallen players for duels or cooperative play. Multiplayer components include asynchronous elements, such as fighting revenants to obtain rare gear, and direct co-op play where players can summon allies to assist in missions.