Mount Natagumo

Seated at the foot of the mountain, Zenitsu sulks, convinced Tanjiro and Inosuke dislike him for entering Mount Natagumo without a backward glance. His sparrow tries to push him into helping, but Zenitsu only envies the bird and scolds it for not being cute. Realizing Nezuko went into the forest with Tanjiro, he bolts into the woods to find her.

Within the mountain, Tanjiro and Inosuke fight their own comrades. Inosuke mocks them until Tanjiro notices their unnatural movements and concludes an unseen force is steering them. When Inosuke moves to cut them down, Tanjiro stops him, refusing to defile their fellow slayers' bodies, which earns him a headbutt.

When Murata is attacked by two controlled slayers, the boys rush to protect him. Tanjiro detects a sweet odor, slashes near a slayer's back, and severs nearly invisible threads, freeing the body. He directs Inosuke to leap over and cut the remaining strands. Searching for the source, Tanjiro finds tiny spiders spinning threads onto his own arms and realizes they puppeteer the Corps members.

A pale boy descends on his own webbing and warns the slayers not to disturb his family, threatening that Mother will kill them. Inosuke's strike misses, and Tanjiro tells him to ignore the boy and find the controlling demon. Inosuke drives his blades into the ground and uses Beast Breathing, Seventh Form: Spatial Awareness, sensing a female demon in the distance. The boy gazes at the moon, vowing to protect his family's bonds.

This chapter introduces Rui and explains the spider threads behind the controlled slayers. It belongs to the Mount Natagumo Arc, is collected in Volume 4, and is adapted in Episode 15.

Inosuke's Spatial Awareness technique is revealed here, drawing on the heightened sense of touch he developed living in the wild.