"Sanemi, stich up your wounds right now. While you're doing that I'll handle this guy" Gyomei said. "Thanks" Sanemi said as Asia came to his side to heal him. Gyomei started twirling his frial and axe. He threw his spiked frail at him as he used his axe to go for Kokushibo's neck. Kokushibo ducked the attack but Gyomei was already going after him with his spiked frail.
Kokushibo dodge the attack but Gyomei used his chain to tie it around his neck, pulling his sword to his face. 'I can't cut this chain!?' Kokushibo said as he tried to cut it. Kokushibo went underneath the chain as it pulled off a little bit of his hair. Gyomei threw his axe frail at him but Kokushibo dodge it. He went for his neck but Gyomei jump over him. He tried going for his neck again but Kokushibo dodge it.
Gyomei was able to tie his chain around his sword and was able to break off the blade. Kokushibo was still able to use his moon breathing as one of his moon disks slice Gyomei's face. Kokushibo's sword started regenerating as he said "It even regenerate right away when broken. Attacks are pointless. Pathetic human."
"I wanted to save this for Muzan, but if I lose now, I'll have gained nothing" Gyomei said as he put his arms in an x. "I have to use it now!" he shouted as his demon slayer mark appear on his arms.
"I see, you too are a marked one. Too bad" Kokushibo said. "Too bad?" Gyomei said. "From what I've seen, I'd say your age is around eighteen" Kokushibo said.
A/N: The demon slayers are teenagers in this story. I'm pretty sure you guys know that by now, but just letting you guys know
"Those who are mark ones usually die before the age of twenty five. To make things short, those marks decrease your life spans."
"All the mark ones understand already" Gyomei told him. "But I realize something. While we've been talking, you told one lie. Their was an exception. There was one who had the mark and live past twenty five and is still alive." Kokushibo was shock for a moment and Gyomei said "Shock you didn't I? It appear I was right." He then vanish before appearing beside Kokushinbo. "Was I?" he asked as he was standing next to him.
They started battling each other as Asia finished healing Sanemi. "Remember, I can only heal wounds. I can't help regain stamina" she reminded him. "I know, but I still got to go out there and kick his ass" Sanemi said as his mask appear on his cheek.
Sanemi ran towards Kokushibo and slice at him. Kokushibo dodge hit attack and immediately dodge an attack from Gyomei. Kiba ran and slice Kokushibo on the waist. Muichiro ran and stab him in the stomach. "Genya, now!" he shouted. Genya shot his gun at him, injecting him with a special bullet. From inside that wound, a tree grew wrapping it all around him.
Everyone started rushing towards him as he then roar. 'He's going to attack!' Gyomei said in his head. 'Shit! Who knows what he can do!' Sanemi said in his head. Before anything happens, time freezes. "Go guys, I stop time!" Gasper shouted as he was hiding behind a pillar this whole tier time. "Thank you young one!" Gyomei shouted as he threw his axe frail onto Kokushibo's neck. Sanemi slammed his sword onto his neck as Kiba help Muichiro hold him down.
With all their strength, they were able to decapitate him. "We did it!" Muichiro shouted. Time unfroze as Kokushibo didn't know what happen. "I'm not done with him yet! I'm going to slice him until theirs nothing left!" Sanemi shouted but stop when they saw he was still moving. His body started changing as he grew tentacles like things on his back and spider like legs all over his body. Even his face was more monster like with him having one big horn and one little horn on his forehead.
"No way, that bastard regenerate his head! Damn it!" Sanemi shouted. "Just keep attacking! His head just came off so his body must be fragile!" Gyomei shouted. "He isn't regenerating as fast as Muzan, so go for the neck!" As they were rushing towards him, the spot where Muichiro stabbed him was turning into dust. With one swing, Gyomei knocked off his head, as Sanemi slash off an arm.
His body was finally turning into dust as Sanemi was still going after him. "Sanemi calm down, he isn't regenerating no more!" Gyomei shouted at him. He grab him and said "It's over. Upper moon one is defeated."
Sanemi was calming down as he was trying to control his rage. "I can't believe it, we killed upper moon one. The strongest of the upper moon" Kiba said. "We all work together to defeat him" Muichiro said. "We didn't do a lot though" Asia said, referring to her and Gasper. "What are you talking about? You guys did a lot too. You heal all our wounds so we can keep fighting. If it weren't for Gasper, some of us could had die from his incoming attack" Genya told her.
"This isn't time to be celebrating. This fight isn't over, until Muzan is defeated" Gyomei told them.
Back with Tanjiro and the others, they heard the news of upper moon one's defeat. "Yes, I knew Kiba would get stronger! I'm so glad they defeated him!" Rengoku said. "All the upper moons should be defeated then. All we have to deal with now is Muzan himself" Xenovia said. They then stop when they saw a long white hair man standing across from them.
"Muzan!" Tanjiro said shock.
Tanjiro was panicking because he was standing in front of the man who killed his family. But it wasn't only that, it was also because this wasn't the Muzan he knew. This Muzan had a scarier aura then before. Tanjiro held his sword tighter and got angry. "Tanjiro, calm down" Giyu told him. "Listen to him Tanjiro, we're all afraid right now" Rengoku said in a serious tone.
"You're so persistent" Muzan told him. "And I'm getting sick of all of you, and I'm losing my patience. You're always yapping about avenging your parents or your children or your siblings. Isn't it enough you're still alive?" That made them angry. "How can you say that?" Tanjiro ask him. "Think of it as if they simply met with disasters. Rain, wind, volcanoes, earth quakes, no matter how many people they kill no one seeks revenge against them. Besides, the dead will not return to life. So give up your grudge, just make a living and pursue a quiet life. That's what most people do, why not you?"
"Muzan, we can not allow you to exist anymore" Rengoku said in a cold tone.