Tanjiro Kamado and Inosuke Hashibira vs Spider Demon (Mother) was a battle that took place on Natagumo Mountain. It focuses on the battle between Demon Slayers Tanjiro Kamado and Inosuke Hashibira against the Mother Spider Demon.
As Tanjiro Kamado and Inosuke Hashibira wander into Natagumo Mountain, Inosuke looks at his hands and sees cobwebs all over it. The two Demon Slayers look at their surroundings and see spider webs everywhere with white spiders. Coming to Inosuke's frustration, Tanjiro tells Inosuke that due to him joining his way into Natagumo Mountain, he thanks Inosuke and feels greatly encourage into finishing the mission.
Witnessing the Mother Spider Demon accept her defeat, Tanjiro changes the grip of his Nichirin Blade and uses the Water Breathing, Fifth Form: Blessed Rain After the Drought on the Demon, beheading her mercifully.