Mount Natagumo

Zenitsu has been told Nezuko is Tanjiro's sister and develops a crush on her. A Kasugai crow comes after the doctor says they're healed and tells the three to go to Mt. Natagumo. They come in sight of the mountain, though Zenitsu is too scared to go on. Tanjiro smells something and runs to it, Zenitsu forced to follow so he isn't left alone. They find a wounded Demon Slayer collapsed on the path but he is yanked into the trees by threads attached to him. They find another terrified demon slayer, Murata, who tells them ten higher ranked demon slayers, including him, came to the mountain, but they started killing each other. An exhausted Kasugai crow is shown on the lap of the Demon Slayer's commander, who notes many have been killed and thinks the Twelve Kizuki may be there. He sends two of the Hashiras (the best swordsmen): Tomioka Giyū and Shinobu to the mountain as backup. Meanwhile, Zenitsu still sits on the path, having been left when Tanjiro and Inosuke ran forward. He cajoles himself into going when he realizes Tanjiro took "his Nezuko" into the mountain. At the mountain, the captured Demon Slayers walk out from the trees and start attacking Tanjiro's group. Tanjiro stops Inosuke from attacking as some are still alive. He smells the threads attached to them and realizes that's how they're being manipulated. Inosuke frees them but a demoness, the Mother of the spider family, sends her spiders to reattach the puppet strings to the Demon Slayers. A white-haired demon boy, Rui, suddenly appears above them, standing on threads, and says Mother will kill them before leaving. To himself, Rui says no one will stop the five of them from living as a happy family. While Tanjiro and Murata keep the controlled Slayers busy, Inosuke uses his Spiritual Awareness to find Mother.