In the past, Shinobu and Kanao converse about if they ever encountered Upper Moon Two. Shinobu believes if she encountered him, and Kanao happened to fight alongside her, she would need to be eaten first, shocking her younger sister. Kanao pleads that she and her would fight the demon together, only for Shinobu to respond back to abandon those thoughts. Though she knows an Upper Moon Demon is as strong as three Hashiras at minimum, according to their late sister Kanae, Upper Moon Two is gluttonous, with an obsession for eating women.
Shinobu knows if the demon faces a Hashira with great abilties, a body in excellent condition and is a woman, he would definitely eat her, worrying Kanao further. She tells Kanao that her body is currently concentrated with wisteria poison. As Kanao tells her she is also willing to go through the same thing, Shinobu tells her it is impossible to reach her level; she had been absorbing the poison for over a year. Shinobu confesses she was the first to do such a feat, herself unsure of the potential side effects in the future and unsure if her plan would work on an Upper Moon or even Muzan. She states her sword has 50 millilitres of poison. But whatever demon consume her would also consume her 37 kilograms worth of poison in her body weight.
Doma collapses further from the effects of Shinobu's poison, his arm falling off, his bones melting and his regeneration failing. He realises he never felt the poison circulate through him until now. His ice dolls soon fracture and collapse as well, to Inosuke's confusion. Kanao realises Shinobu's poison is working and they now have Doma cornered.
Shinobu tells Kanao she doesn't know even if a life's worth of expertise on poison would work on an Upper Moon Demon. Kagaya Ubuyashiki himself had deemed it impossible but advised her to consult with a demon for further knowledge. Shinobu tells her sister, if the poison did start working, she must never let her guard down still, adding the only sure way to kill Upper Moon Two is sever his neck. She knows she will definitely weaken him and tells Kanao to deal the finishing blow.
Kanao becomes assured she will kill Upper Moon Two and resolves to not let Shinobu's life go to waste. As she and Inosuke converged on Doma, he summons his final technique, Blood Demon Art: Rime - Water Lily Bodhisattva. With the two stunned at this new threat, the giant ice figure slams down onto the cult room pond, sending Inosuke and Kanao flying back. Kanao realises if they get forced away from the fog, Doma will have the time to recover. And if they entered the fog and inhaled it, they would no longer be able to fight. However, she notices though Doma's bodhisattva is powerful, it's shoddy; Doma has lost all his precision and creating it was a last ditch effort. She decides to use her own last technique and remembers her last moments with Shinobu.
Shinobu warns her that using the technique might blind her; eyeballs are delicate, with very thin blood vessels and nerves, telling her not to endanger and burden herself by releasing such power. Kanao rejects her warning, asking why should she worry about her vision when Shinobu gave her own life. She calls her sister a sweet and honourable person, declaring she wanted to protect her with her life, and she wanted her, Aoi, Sumi, Kiyo and Naho and herself to all go home together.
Kanao activates Flower Breathing: Final Form - Equinoctial Vermillion Eye, causing her eyes to flush full of blood and her perception heightened even further than ever. The giant bodhisattva becomes slow in her eyes; she can see its hand about to slam down. She realises her scleras are turning red and quickly slices up the ice figure's hand to reach Doma. As she swings at Doma's decaying head, the bodhisattva turns back and blasts Kanao with the icy fog, freezing her back and arms. Her sword reaches his neck but she can no longer swing further with her arms stuck frozen. Inosuke sees this and uses a new technique, Sudden Throwing Strike, hurling his blades at Doma.
His swords hit Kanao's, driving the blade through Doma's neck, decapitating him.