Tsuzumi Mansion Arc

The Tsuzumi Mansion Arc is the fourth main storyline of the Kimetsu no Yaiba manga, running from Chapter 20 through Chapter 27 and adapted in Episodes 11 through 14 of the first anime season. It follows the events of the Asakusa Arc and leads directly into the Mount Natagumo Arc.

The arc takes its name from its central setting, a remote mansion on a mountainside controlled by a demon who carries drums embedded in his body. It is best known for introducing two of the series' lead characters and for its disorienting, room-shifting central puzzle.

Climbing a mountain alongside the timid Zenitsu Agatsuma, who has only recently attached himself to the group, Tanjiro reaches a strange residence. A pair of frightened children plead with the two slayers to rescue their older brother, who has vanished somewhere within the walls.

Once inside, the layout refuses to stay still. Whenever the drum demon strikes one of the instruments fused to his frame, entire rooms spin and rearrange, turning the house into a living maze. Separated and disoriented, each fighter is forced to face a demon of his own while searching for the missing boy.

During the chaos Tanjiro encounters a brash, energetic young man wearing a boar's-head mask. This aggressive newcomer, Inosuke Hashibira, throws himself into the fighting on his own terms, setting up the trio dynamic that defines much of the series. Tanjiro also confronts Kyogai, the master of the mansion, whose drum-driven attacks turn the building itself into a weapon.

By the close of the arc the abducted child is recovered and the mansion's threat is ended. More importantly for the larger narrative, the events here cement Zenitsu and Inosuke as fixtures alongside Tanjiro, completing the core group of young slayers who travel together from this point forward.

The arc also introduces several supporting figures connected to the rescue, and it leaves Tanjiro and his new companions poised for their next, far deadlier assignment on Mount Natagumo.