Demon Slayers vs Muzan Kibutsuji: Part 1

Demon Slayers vs Muzan Kibutsuji is a battle that took place in both the Demon Slayer Corps Headquarters the Infinity Castle which occurred between a number of unnamed Demon Slayers, Tanjiro Kamado, Tamayo, and the Hashira against the Demon Lord Muzan Kibutsuji.

Battle
As Muzan continues to regenerate, he sees multiple pieces of burning flesh around him. These pieces of flesh are in fact Tamayo's Blood Demon Art: Flesh Seeds. The flesh seeds then burst into black flesh trees with spikes puncturing his flesh so he can't pull them out. As Muzan attempts to absorb the Blood Demon Art, Tamayo rushes in and jams her fist into his abdomen. She then questions him what she held in her fist that Muzan absorbed, a special drug that reverts Demons back to humans. Muzan thought that it was impossible for demons to become humans again but Tamayo has finally solved it with help from Shinobu Kocho. Muzan then tells Tamayo that she is very stubborn and that her hatred towards him is unjust, due to her killing her family herself and not Muzan. She responds that due to Muzan turning her into a demon and that her only intent on becoming a demon was to survive her illness and see her children grow up. Because of this, she will atone for her sins and will sacrifice herself so both Muzan and her will die, ending the demon race forever.Suddenly, Gyomei Himejima appears and crushes Muzan's head with his spiked flail. However, with Kagaya Ubuyashiki's prediction, Muzan regenerated his head with little to no difficulty. Gyomei even stated that due to the sound of his flesh regenerating, he is unlike any other demon he has ever faced. Thus Gyomei knows that he, Tamayo and the Demon Slayers have to restrain Muzan until the sun rises. Muzan uses his Blood Demon Art: Black Blood - Brambles at the Stone Hashira in which he reflects it with Stone Breathing: Third Form - Stone Skin. Sanemi sees the demon lord Muzan and screams, asking what he did to Kagaya with the other Hashira worried sick as well. Gyomei screams at the Hashira that the demon who infiltrated their HQ is none other than Muzan Kibutsuji himself and that he will not die no matter how many times he's beheaded. This greatly shocks all the Hashira beyond measure due to them never seeing Muzan in the flesh, however with Tanjiro, instead of being shocked he's furious with seeing Muzan's face once again. All the remaining Hashira use their respective Breathing Styles in order to cut Muzan down: Muichiro Tokito with Mist Breathing: Fourth Form - Shifting Flow Slash, Shinobu Kocho with Insect Breathing: Butterfly Dance - Caprice, Obanai Iguro with Serpent Breathing: First Form - Winding Serpent Slash, Mitsuri Kanroji with Love Breathing: Fifth Form - Swaying Love — Wildclaw, Giyu Tomioka with Water Breathing: Third Form - Flowing Dance, and Sanemi Shinazugawa with Wind Breathing: Seventh Form - Gale — Sudden Gusts. Tanjiro Kamado joins in the fight and uses the Hinokami Kagura: Sunflower Thrust. Thus a huge barrage of Demon Slayers surround Muzan.