Shinobu Kocho vs Spider Demon (Daughter)

Shinobu Kocho vs Spider Demon (Daughter) was a battle that took place on Mount Natagumo. It focuses on the battle between the Insect Hashira Shinobu Kocho against Daughter of the Spider Family.

Prologue
As Daughter runs away from the fight between Tanjiro Kamado and Rui, she reminisces on the events that have led to this moment, recalling when Rui first met her, everything that happened throughout her time in the Spider Family, informing Rui of the deaths of her "Mother" and "Brother" and his wrath upon realizing they have never lived to his expectations. Soon after, she runs into Murata, much to his surprise. She immediately discerns that he is a Demon Slayer and captures him with an acidic cocoon, her own Blood Demon Art. He quickly attempts to stab and slash open the cocoon to escape but it backfires. Daughter then comments that it is futile to escape due to the cocoon being incredibly durable despite its softness. Inside, Murata sees thick lime-green liquid oozes out of the threads, slowly filling up the cocoon. The Spider Demon sadistically explains that the liquid will first erode his uniform, then his body, before she will devour his remains.

Suddenly, Shinobu Kocho appears right behind the demon and inquisitively wonders if the threads come out from her palms, along wishing her a good evening and commenting about the beauty of the moon as well

Battle
Startled, Daughter quickly steps away from Shinobu. She attempts to capture her with her acidic cocoon, but Shinobu gracefully dodges all of her silk and approaches her, closing the distance. Upon getting within range, she repeatedly kicks Daughter to the ground, pinning her down. Shinobu reflects that the Spider Demon doesn't want to become her "friend", to which the demon quickly begs for mercy. Daughter claims that she is being threatened by someone and will be killed for any defiance, causing Shinobu to appear concerned.

Shinobu states that she will be willing to spare her, to Daughter's great surprise, but adds that she must asks a few questions beforehand. Coldly staring at the demon, the Insect Hashira asks how many people she has killed. Scared, Daughter quiet answers that she's killed five, as she begins to tear up. She repeats that she had no choice and was ordered to do so but Shinobu brushes aside her words and asks that she do not lie. The demon maintains that she has only killed five but Shinobu informs her of finding hordes of cocoons and at least eighty dead humans captives just from the direction she came through in the forest.

Seeing the frightened demon staying silent, Shinobu mentions she is not angry and simply trying to get an accurate toll. When Daughter asks about the importance of knowing how many she has killed, Shinobu responds that she needs to receive the proper punishment in order for them both to be friends. Shinobu states that she could either gouge out her eyes, slash her stomach to rip out her insides, and torture her for each of her victims. Daughter begins to panic at her impending fate, while a sly Shinobu adds that she will not die from her torture because she can heal. Disturbed and fearful of her future torture, the Spider Demon engages at Shinobu and attempts to capture her again, only for Shinobu to quickly evade it again, while lamenting the demon's poor decision. Seeing that they can never be friends, she unsheathes her sword. When the demon tries to fire her silk again, she is unable to spot the Hashira. Looking up, she sees Shinobu leaping high into the air before lunging towards her with numerous butterflies behind her. She suddenly finds herself surrounded as dozens of butterflies fly pass her, with a single one landing on her finger. When she moves in for a closer look, the butterfly begins to bleed. causing blood to drip from her finger and her body to change. In actuality, Shinobu uses her Insect Breathing, Butterfly Dance: Caprice on the Spider Demon. Daughter immediately touches her neck to see if she was beheaded, to which she realizes she was not. She questions as to how and why the Insect Hashira didn't behead her, to which she concludes that Shinobu doesn't have the necessary strength in order to behead a Demon. This greatly boosts the Spider Demon's confidence in defeating her, but as she was about to attack Shinobu, she is hit by a wave of pain and sees her blood vessel changing. As her wounds begin bleeding, internal bleeding appears throughout her body, and her condition rapidly deteriorates, Daughter lets out one final scream of agony before slumping to the ground, the last of the Spider Family defeated. Shinobu happily mentions that she shouldn't feel safe if she has not been beheaded, as there are Demon Slayers like her who wield poison instead.

Aftermath
After confirming that Daughter is indeed dead, Shinobu quickly frees Murata from his cocoon prison. Upon seeing the demon on the ground, he wonders if she should finish it off, only for the Hashira to state that she is already dead from the poison she used. As an embarrassed and nude Murata slinks away, Shinobu turns her attention to the demon Daughter had said has been ordering her, wondering if the demon has been reached by her partner Giyu Tomioka already.