Infinity Castle Arc

This arc forms the first half of the larger Final Battle Arc and stands as the eleventh story arc of the series. It covers chapters 140 through 183 of the manga and has been adapted as part of a feature film trilogy centered on the Infinity Castle.

The entire arc takes place inside the Infinity Castle, a vast and constantly rearranging stronghold that separates the slayers and forces them into isolated battles against Muzan's strongest servants.

The Corps descends into the castle intent on reaching Muzan and severing his head. Shinobu Kocho takes on Doma, the Upper Rank 2 demon, despite knowing her poisons have little effect on him, driven by the chance to avenge her older sister. Nearby, another demon bars Zenitsu's path, drawing him into his own fight.

Tanjiro and Giyu Tomioka face Akaza, the Upper Rank 3, whose overwhelming power keeps them on the defensive until Tanjiro reaches the heightened state his father once described, the Transparent World, which lets him finally seize the initiative. Elsewhere Kanao Tsuyuri continues the battle against Doma, Obanai Iguro and Mitsuri Kanroji cut through the shifting chambers, and Muichiro Tokito fights alongside Sanemi and Genya Shinazugawa against a foe who recognizes Tokito though Tokito does not know him.

The fights within the castle account for the remaining Upper Rank demons as the slayers press relentlessly toward Muzan, paying a heavy price in the process. Each duel resolves long-running personal vendettas held by members of the Corps.

The arc flows directly into the Sunrise Countdown Arc, the second half of the Final Battle, where the conflict spills out of the fortress and the slayers race to keep Muzan exposed until the sun can finish him.