Episode 15

Mount Natagumo (那田蜘蛛山, Natagumo Yama) is the 15th episode in the Kimetsu no Yaiba anime TV series.

Short Summary
Their next destination is to the north-northwest. Tanjiro and Nezuko head towards Mount Natagumo with Zenitsu and Inosuke. This mountain is covered with spider webs and is swarming with innumerable spiders. Leaving the cowering Zenitsu behind, Tanjiro and Inosuke head up the mountain where they run into fellow Demon Slayers entangled in spider webs.

Meanwhile, a crow flies back to Kagaya Ubuyashiki to report the situation and how many of the Demon Slayers have been taken down. Ubuyashiki seems it necessary to send Pillars. He asks Giyu and Shinobu, who are sitting behind him in the room, to take up the task, both of whom accept. Shinobu then wonders out loud if it were only possible for demons and humans to get along, asking Giyu if he agreed. Giyu replies, saying such a thing would be impossible as long as demons continue to eat humans.

Long Summary
Zenitsu has been told Nezuko is Tanjiro's sister and develops a crush on her. A Kungai crow comes after the doctor says they're healed and tells the three to go Mt. Natagumo. They head out. They eventually 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 Kungai 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 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 sends her spiders to reattach the puppet strings to the Demon Slayers. A white-haired demon boy suddenly appears above them, standing on threads, and says mother will kill them before leaving. To himself, he 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 the demoness responsible.

Characters in Order of Appearance

 * Nezuko Kamado
 * Zenitsu Agatsuma
 * Tanjiro Kamado
 * Inosuke Hashibira
 * Hisa
 * Older Sister Spider Demon
 * Father Spider Demon
 * Mother Spider Demon
 * Murata
 * Kagaya Ubuyashiki
 * Nichika Ubuyashiki
 * Hinaki Ubuyashiki
 * Shinobu Kocho
 * Giyu Tomioka
 * Rui