Kokushibo's Final Stance

A False Battle

Muzan took the first strike at the hashira. His speed was unreal and even in his first attacks, the hashira were facing trouble adjusting to his speed. Muzan used his arms and extended them in all sorts of ways to confuse his opponent. His arms could contort, bend, extend, and shape into anything he wanted to and when things couldn't get any worse, blades attached to his back whipped around at blinding speed. Everyone took notice and kept their distance and couldn't be able to get anywhere near him. 

"This is bad!" Giyu said to himself. "There is no way we will be able to slice off his head if he's kept in this palace where the sunlight can't reach him." Muzan kept up his attacks and severely wounded Tanjiro with a deep slash across his torso. All the other hashira were keeping pace and even got a couple of blows on Muzan, unfortunately, his speed of regeneration was so fast that they couldn't even tell that they hit him. Gyomei's axe and iron ball launch at Muzan, Muichiro uses all the mist breathing technique's in quick succession, Sanemi uses his powerful wind breathing techniques, and Giyu combining his breathing style with Sanemi's wind breathing for a more powerful punch. Swords and blades clashing in the palace were heard for miles. Every hashira was at the top of their game to keep up with Muzan and in what seemed like an instant, everyone gained their demon slayer mark and everyone's speed was increased 10 fold. Muzan was not deterred in the slightest and kept the attack going.

15 minutes have gone by and no one has come close to decapitating his head. Muzan's bloodshot red eyes piercing through everyone's soul sent the slightest shiver through everyone's body. Tanjiro came in for the attack with one of his Hinokami Kagura breathing techniques and this quickly sent a shiver down Muzan's spine. His eyes widen as he could see a ghost from his past, Yoriichi Tsugikuni. "A ghost!" Muzan said with fear in his voice. "This is what you wanted Kokushibo, this is your once-in-a-lifetime opportunity to take revenge on the brother that you hate so much..." Tanjiro kept the attack high and everyone else was starting to chip away at Muzan's skin. Muichiro was able cut off both of Muzan's arms in a blink of an eye and Gyomei sent his iron ball toward Muzan's head. Muzan dodged the attack by a hair and only a small bit of hit face came off. 

What seemed like magic to a few hashira, they could see a strange world that saw right through Muzan's body. He had seven hearts and five brains in his body, a true monster. Giyu, Tanjiro, Muchiro, and Gyomei were able to see this transparent world and knew they had to strike at the 13 spots at the same time to take down this monster. All of them readied for attack and used their various breathing techniques. Muzan saw what was about to happen and tried to counter-attack with his whips, but something strange started to happen. Small pellets were sent in Muzan's direction and like living things dodged Muzan's attacks and into his skin. Genya ate a part of Muzan's face that was chipped off and gained immense power that almost made him sick. He used his gun and aimed it toward Muzan. Muzan was furious that he didn't pay any attention to Genya, but it was too late since the bullets were in his body and started to suck the blood out of Muzan and grew tree stumps that even he couldn't escape from. 

All the hashira came in for the attack and sliced off their opponent's limbs and head in quick successive order. Muzan fell to the ground and started to turn to ash. His face didn't show any signs of sadness or anger, but rather he uttered these last words. "You fellow Hashira are not even close to my level! I was poisoned and I'm not even the demon king anymore. In other words, all of you are dead and can all be sent to hell for all I care!" Muzan's body disappeared and all the hashira knew that something was up since that fight although the most challenging in their lives, was a lot easier than they all expected. All of them were filled with anxiety and got ready for the possibility that another demon even stronger than Muzan would appear before them.