Demon Slayers vs Muzan Kibutsuji: Part 2

Demon Slayers vs Muzan Kibutsuji: Part 2 is a battle between Demon Slayers Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, Kanao Tsuyuri, Hashira Giyu Tomioka, Mitsuri Kanroji, Obanai Iguro, Gyomei Himejima, Sanemi Shinazugawa, and Demon Yushiro along with the remains of the entire Demon Slayer Corps against Demon Lord Muzan Kibutsuji. It occurs immediately after the Infinity Castle is destroyed.

Prologue
Kiriya Ubuyashiki realizes that Tamayo couldn't endure long enough to hold Muzan down and the medicine that both Shinobu and her concocted was unsuccessful in reverting Muzan back into a human. Kanata informs Kiriya that the first team of Demon Slayers have arrived where Muzan's flesh cocoon is resting and a second group is following them. Kiriya immediately orders her to tell the Demon Slayers to stay away from Muzan until all the Hashira arrive. Multiple teams of Demon Slayers surround the capsule of flesh that Muzan is residing in. A Demon Slayer hears an order from a Kasugari Crow that all the Demon Slayers should standby and not engage until the Hashira arrive as they have no idea on what can happen. Suddenly, Muzan emerges from his flesh cocoon with a brand new appearance, his hair being far longer and being silver white due to his accelerated aging. He also has numerous jaws all over his body with sharp white fangs used to consume human flesh and blood, and is holding Tamayo's disembodied head on his right hand. Muzan massacres the dozens of Demon Slayers currently within his vicinity as they try to retreat from his location. Kiriya attempts to order them through a Crow for them to fall back. However, Muzan murders and consumes all the Demon Slayers within their groups and beheads the Kasugari Crow that gave the orders to retreat.

Muzan notes that due to him aging over a millennia, he has lost the desire to taste food however due to him starving for taking the force of the Ubuyashiki explosion and using his energy to nullify Tamayo's drug he now adores the taste of flesh and blood. He compliments Kagaya for "deliberately" bringing him humans to feast and to regain his strength and stamina. He even wants the new successor to bow down so he could possibly turn him into a demon since practically all of his subordinates are killed. Back at what's left of the Demon Slayer Headquarters, Kiriya commands his two younger sisters to make the second troop of Demon Slayers retreat and keep their distance away from Muzan as he'll only regain more strength and stamina from consuming more flesh. Muzan lifts Tamayo's disembodied head and mockingly points out that her "drug to turn back into a human" had no subtle change to his body. He also imitates her words that he'll fall into hell and that hundreds of people have spoken similar words to him and that it has never happened once. Tamayo sheds tears and begs Muzan to give back her husband and children, in which he bluntly tells her to die and head to her family that "she" killed. Thus, Muzan crushes Tamayo's skull and consumes her blood and cells. Due to Yushiro's Blindfold being within the vicinity, Yushiro immediately loses his balance and topples over onto a wall with nearby Demon Slayers questioning whether he is alright. Muzan continues massacring more and more Demon Slayers within his path continuing to gain more stamina. Kiriya screams and begs the Demon Slayers to fall back so they can not give Muzan more strength and sustenance along with Tamayo's sacrifice to not be a waste. Muzan notes that every single member of the Twelve Kizuki was of no use to him and that he'll slaughter the Demon Slayer Corps himself. Kiriya panics and blames himself for giving the wrong orders and letting all the Demon Slayers be slaughtered by Muzan Kibutsuji. From this, he loses all his concentration on preparing the remaining Demon Slayers in order to take down Muzan. During all of this, Kanata repeatingly calls out his name for new orders but Kiriya does not respond, presumably not even knowing that she was calling him. Thus, Kanata slaps Kiriya out of his self-doubting situation much to Kuina's shock and yells at him to keep it together, even calling him "Oyakata-sama". She then states that the fight isn't over yet and that he still needs to give orders to the Demon Slayer Corps, whatever success it brings. This brings back Kiriya's confidence and concentration, thus he commands that all the Hashira must go to Muzan's location immediately along with all the Demon Slayers as reinforcements. A Kasugarigarasu Crow gives intel that Muzan has been fully revived and that all the surviving Hashira must gather at Muzan's location. Mitsuri Kanroji and Obanai Iguro are the first to hear this message, with Mitsuri question herself what both she and Obanai have been doing the entire time while Muzan was revived. Obanai questions what effort he has done due to that Muichiro Tokito and Genya Shinazugawa have sacrificed themselves in order to defeat Upper Rank 1, Kokushibo. He points out that Nakime is not exactly harming them but stalling them for time so the least amount of Hashira can fight Muzan Kibutsuji. Obanai quickly grabs Mitsuri in order for both of them to get out of the situation they're in. Quickly realizing this, Nakime uses her Blood Demon Art: Castle Manipulation in order to teleport Muzan Kibutsuji to Tanjiro and Giyu's location. Tanjiro sees Muzan in the flesh and rage immediately fuels inside of him while Giyu tells him to calm down. Muzan calls them incredibly persitent which sickens him to his core, as he always sees humans as beings who only care about vengeance for the deaths of their loved ones. With that being said, he says that those who are alive should be grateful for being alive and should stop wasting their lives on vengeance. This greately shocks Giyu and Tanjiro as Muzan compares himself as a natural calamity. He clarifies that humanity cannot gain revenge on disasters no matter much damage or how many lives it takes away from the world. Tanjiro calmly points out that Muzan is being that does not deserve to even exist in the first place. Tanjiro can not believe that he has never felt this cold towards a living being once in his life. He points out from Gyomei's explanation that Muzan cannot die from decapitation, from this he tries to figure out how they can expose Muzan Kibutsuji to the sun. The problem being that they have no clue on how to bring Muzan out of the Infinity Castle. Muzan immediately transforms his arms into long spiked tendrils that function like whips and flails them at both Tanjiro and Giyu. Giyu uses the Water Breathing: Eleventh Form - Dead Calm in order to repel the flailing tendrils but gets cut in many places in his body along with Tanjiro. Tanjiro notes that Muzan's attacks are unbelievable in destructive power and lethality, as he is only dodging by instinct alone. Tanjiro however keeps his tenacity going and attempts to go through Muzan's tendrils in order to harm him in some way. Just as when he got within striking distance of Muzan, one of his arms slash past and cuts Tanjiro's right eye knocking him onto the ground. Before Muzan kills Tanjiro with one of his tendrils, Giyu grabs hold of Tanjiro and tells him that slashing Muzan is absolutely pointless since his strength can't even be compared to the Upper Ranks. Muzan scoffs at the Demon Slayer's efforts on stalling him until the sun rises as the sun can't penetrate deep within the dimensional reality of the Infinity Castle along if three Hashira are enough to stall him. This confuses Giyu and Tanjiro as Muzan specifies that both Mitsuri and Obanai were killed by Nakime when she crushed both of the lower halves of their bodies. Muzan keeps attacking the two Demon Slayers with his tendrils with Tanjiro falling over multiple times due to him not being able to his surroundings. Suddenly the Love Hashira Mitsuri Kanroji drops through the ceiling and stops Muzan's assault by using her Love Breathing: Sixth Form - Cat-Legged Winds of Love. Mitsuri believes that her Love Breathing attack harmed Muzan in some way, but the demon lord is completely unscaffed, coming to her surprise. Obanai appears helping Tanjiro get back up and tells him to back out of the fight if he keeps getting knocked down. Tanjiro is relieved to see Obanai and Mitsuri alive, while Muzan is both confused and livid at the fact the two Hashira that Nakime supposedly killed are still alive. Muzan shouts Nakime's named and demands her what she is doing at that moment, with Yushiro placing his Blindfold technique in front of her singular eye along with his fingers jammed into her skull possibly touching her nerves to command the Infinity Castle upwards towards the surface. Yushiro with his eyes blood red tells that Muzan has committed the gravest sin in the world, taking Tamayo away from him. This makes Yushiro scream in grief telling him to repent immediately and that he will be erased from the face of the earth. Giyu takes this opportunity to try to harm Muzan Kibutsuji with the Water Breathing: Fourth Form - Striking Tide along with Obanai using his Serpent Breathing: First Form - Winding Serpent Slash. This distracts Muzan as he doesn't know whether to kill the Hashira or his remaining Twelve Kizuki member. The floor where the main battle is taking place between Muzan and the Hashira suddenly open, making everyone fall. Muzan lifts his right arm and closes his fist, crushing Nakime's face and most parts of her skull. Because of this, the entire Infinity Fortress is collapsing while Yushiro knows that he can still take everyone outside as not all of Nakime's cells have disintegrated yet. With that happening, no one is able to have solid footing while Mitsuri tries to presumably use another Love Breathing technique on Muzan which he dodges. Muzan flails his tendrils all over the place and slashes Tanjiro in his torso and nearly kills Mitsuri by impaling her face but Obanai pushes her out of the way, only cutting off a small piece of her haori. Tanjiro also javelin throws a broken Nichirin Blade from one of his fallen comrades at Muzan's skull, piercing it completely much like how he did against Akaza. Just as that happens, the Infinity Castle pierces through the terrain of the real world, flinging absolutely everyone in all directions.

Battle
Tanjiro opens his eyes and sees the night sky realizing that they are indeed on the surface, however the landed on a compact city with many innocent civilians. This is completely out of what Kiriya Ubuyashiki predicted where everyone would end out when the Infinity Castle would pierce through the world. Although since Yushiro and Muzan where in a tug-of-war on who could control Nakime, he says it is a miracle that they were even able to go to the surface. Kiriya asks Kuina how long there is left until dawn, with her pulling out a gold pocket watch and with sweating dipping down her face says in one and a half hours. This petrifies Kiriya as there is still so much more time left until the sun rises. A Kasugai Crow tells everyone that an hour and a half is left until dawn breaks. As the Hashira and all other Demon Slayers make out of the rubble, Muzan unleashes a large shockwave to push all the rubble on top of him. He angrily asks the Demon Slayers if they will really keep him in company until the sun rises and mockingly requests them to try. The Hashira dodge Muzan's attacks and retaliate the Demon lord with Obanai using the Serpent Breathing: Third Form - Coil Choke, Mitsuri using her Love Breathing: Second Form - Love Pangs and Giyu using the Water Breathing: Eighth Form - Waterfall Basin. Obanai was able to slash his Nichirin Blade past Muzan's neck, but to no avail as the moment his blade cuts Muzan's neck it regenerates instantaneously. This confuses Mitsuri to the point where she doubts that Muzan is not being cut down, whereas Giyu knows that Muzan is being cut but regenerates his wounds instantly. Muzan finds this the perfect opportunity to strike and kill all the Hashira. Just as the Hashira were about to be mauled by Muzan, dozens of Demon Slayers come and sacrifice themselves to save the Hashira.

While the Demon Slayers keep sacrificing themselves, one of them tells the others to protect the Hashira with their lives as the Hashira always protected them. Mitsuri cries and yells at the Demon Slayers to stop as there have been too many casualties already. Tanjiro not wanting any more Demon Slayers to die stands up and tries to run back into the fight against Muzan but stumbles and falls, coughing out large amounts of blood. After all the Hashira, Inosuke and Zenitsu were knocked down by Muzan Kibutsuji, Kanao remains the sole fighter in the field despite being on her knees and her Nichirin Blade is broken. She tries to will herself to fight, and just as she prepares to defend against the Demon Lord's incoming strike, Tanjiro Kamado regains his consciousness with the help of Yushiro's medicine, and uses the Hinokami Kagura: Beneficent Radiance to cut off Muzan's arms and rescue Kanao. The two converse, with Muzan being abhorring Tanjiro's wounded appearance, while the Demon Slayer, enraged at his allies' injuries, calls on the Demon to end their long-standing feud.

Tanjiro reflects on his memories and visions, noting that, now that he has seen the actual dance from Yoriichi himself, he has noticed the proper technique and style for performing the dance. He thanks Yoriichi for saving his ancestor and for passing down the Sun Breathing, and realizes that the 12 forms were to be connected until the break of dawn to stall the Demon Lord. Although Tanjiro still doubts his own abilities, due to even Yoriichi not being able to defeat Muzan, he steels his resolve, recalling Kyojuro Rengoku’s words to him to set his heart ablaze. With this, he engages his nemesis with the legendary breathing style. As Tanjiro approaches, he notices Muzan’s new tentacles in his thighs, realizing that the Demon’s shapeshifting abilities led to the defeat of the Hashira. Meanwhile, Muzan enragedly attacks the advancing Demon Slayer, seeing the ghost of the mythical Yoriichi in the young boy. Despite Muzan’s whips slicing Tanjiro, the latter shrugs off the attack, and opens with the Sun Breathing: Dance, Clear Blue Sky and Raging Sun consecutively.

Aftermath
Muzan's defeat while significant, would prove to be a costly victory for the Demon Slayers, leaving scores of members deceased, dozens mauled and heavily injured and many on the verge of death. Muzan, in Tanjiro’s consciousness, is driven by his desire for immortality, and so bequeathes his knowledge and power to the unconscious boy.

Tanjiro turns into a Demon, starting a new battle.