When Rui assaults him with his Blood Demon Art, Tanjiro braces himself for certain death. As his life flashes before his eyes, he suddenly remembers his father's dance, the kagura, and unleashes a new, non-Water Breathing attack. Hinokami Kagura: Dance. Knowing that he’ll be receiving a simultaneous blow from the demon, he uses his new move to slice off Rui’s head. As Tanjiro crawls towards Nezuko, who lies on the ground, riddled with wounds, someone appears before him.
Tanjiro collapses from his wounds and crawls towards Nezuko, who has fallen and isn't moving. He smells blood behind him and realizes he normally smells ash when demons were killed by his sword. Rui stands and puts his head back on. He tells Tanjiro he cut his neck with one of his own threads when he realized he would be decapitated by the Nichirin Blade, which would have killed him. Enraged, he encircles Tanjiro with his Blood Demon Art: Murderous Eye Basket to mince him, only for Giyu to arrive and save him. Giyu congratulates Tanjiro on holding out until he arrived.
Angered, Rui unleashes his most powerful Blood Demon Art: Cutting Thread Rotation, a sheet of threads at Giyu, who uses the Water Breathing, Eleventh Form: Dead Calm to shred them when they reach him. Giyu then easily beheads him.
As the Daughter runs, she remembers when she was being chased by Demon Slayers and saved by Rui, promising to join his family. Rui fed her some of his blood, giving her her current appearance. There were many siblings Rui had shared his blood with and he insisted they pretend to be a family. If they did something Rui didn't like he'd punish them, sometimes by wounding them, other times stringing them up and letting the sunlight kill them, like he did to an Older Sister who tried to run away with the Daughter (and whom she betrayed to keep herself alive). Thus the numbers decreased to five.
The Daughter comes across Murata and ensnares him in her Blood Demon Art: Acid Cocoon, only to be knocked to the ground by Shinobu. After the Daughter begs for her life and blames Rui for her actions, Shinobu asks her how many people which she's killed, saying (smiling all the while) that once she tortures her appropriately for all the people she's killed (gouge out her eyes, rip out her organs, ect.), they can be friends and her sins will be forgiven. The Daughter refuses so Shinobu uses her Insect Breathing, Butterfly Dance: Caprice to approach and cut her neck with her sword. Shinobu's sword is sharp only at the tip as she lacks the strength to behead demons... However, Daughter dies seconds later from the wisteria-based toxin Shinobu invented and coated her sword with. Shinobu then frees Murata from the cocoon.
Tanjiro makes it to Nezuko and drapes himself over her body protectively. As Rui dies, he thinks he made the pretend family because he had no memories of when he was human, and he thought if he could feel a familial bond, his memories would come back. He looks upon Tanjiro and Nezuko, wishing he had what they had.
Characters in Order of Appearance
- The anime goes more into detail of the Spider Family's origin as well as showing one of the Older Sister Spider Demon's memories which was not depicted in the manga.