After the last battle where Muzan got killed and Tanjiro barely made it alive, the remaining Demon Slayer Corps and Pillars had to fight Tanjiro in his Demon King form. Tanjiro's consciousness slowly faded away along with his willpower to fight Muzan's temptation inside him. As he couldn't control his own rage, he began to strike everyone around him without any hesitation. The Corps and Pillars went all out with their remaining energy.
"What are we supposed to do?! He didn't react to our voice at all! said Zenitsu. As Zenitsu use all his remaining energy to use his 7th Thunder Breath form, Tanjiro blocked it without any effort at all.
"Then we got no choice but to finish him right now eh? Then.. Seventh Form: Gale, Sudden Gusts!!" It managed to slash through Tanjiro, but his regen speed made Sanemi attack almost useless. "Then another one.."
"Wait! don't rush yourself, we still need to wake him up.." said Giyuu.
"Stop your gibberish talk and start to see the reality in front of you! He's not Tanjiro anymore, right now he's a demon! Our long mortal enemy since thousand years ago!" Along with Sanemi talk, the others feel broken-hearted because of the truth that he spoke out. It really punches Giyuu in the face to see how Tanjiro became awfully wicked in that form. But Tanjiro didn't wait for their hesitation and began to assault them. He moved in the blink of an eye and got behind Giyuu.
"Too fast, I can't dodge right away.."
As Tanjiro claws nearly strike Giyuu, Zenitsu and Inosuke block it on time.
"Are you okay?!" said Zenitsu.
"Hurry and move your ass away idiot! We can't hold it that long!" said Inosuke.
Kanao and Sanemi began to strike Tanjiro back's while his claw was still blocked by Zenitsu and Inosuke.
"Eighth Form: Primary Gale Slash"
"Fourth Form: Crimson Hanagoromo"
As Tanjiro sense became sharp, he unleashed another tentacle-like weapon from his body that made from his bone. Of course it's not an ordinary bone, because their sword almost broke from that strike alone. Kanao and Sanemi take a back step and wait for a moment to strike again.
In that split second, Tanjiro use his tentacle-like weapon to crush Inosuke and Zenitsu too.
"Can't move my body.."
"Damn it.. Tanjiro.."
In seconds after seeing both of them fall, Giyuu began to use his breath move to protect them from being killed.
"Sixth Form: Whirlpool!"
Of course that did nothing for Tanjiro, but Kanao and Sanemi already got Inosuke and Zenitsu moved away from Tanjiro range. The other corps began to srike Tanjiro, but it ends their life right away. One by one got killed mercilessly by him.
"At this rate all of us are going to hell, can't we do something?" said Sanemi
"I will try to use this drug, so try to back me up." said Kanao.
"Are you sure about that? There's no guarantee he will come back to us."
"Let's do as she said for now, Sanemi."
"Don't forget that we are the only survivor right now, no time to be doubtful, you hear me?"
"I know." said Giyuu
The two Pillars begin to strike Tanjiro with everything they got in the hands.
"Tanjiro, I will save you from that hell now."
"Final Form: Equinoctial Vermilion Eye!"
Kanao began to take a very quick step towards Tanjiro.
"First Form: Dust Whirlwind Cutter!"
"Ninth Form: Splashing Water Flow!"
Tanjiro can feel their murderous intention directed right toward him. So, Tanjiro accepted their challenge and attack both of them with his tentacle-like weapon. While both parties fight so intensely, Kanao succeeded to blink so fast behind Tanjiro back.
"That's it! She made it!" Giyuu talked in his mind.
"With that drugs, everything will be over now.." Sanemi talked in his mind.
Kanao managed to strike the drug to Tanjiro, his movement began to slowed down until he finally stop moving.
"You think we made it?" said Sanemi.
"I hope so, at least that drug didn't have to kill him." said Giyuu.
As Kanao move slowly toward Tanjiro and patted his head, she began to cry.
"Come back to us, Tanjiro. The demons are all gone now, you can live peacefully with your sister."
Inside Tanjiro, Muzan still there, tempting him to become demon and carry Muzan's will.
"Tanjiro, you can go now, but I will take her life along with mine."
"What do you mean!? What are you going to do to her?!
"Rest assured, it will be over in a blink of an eye, I will take control of you with all remaining energy I have to kill this girl who sit beside you right now."
"No! He mention about Kanao!" Tanjiro talked in his mind.
"You won't feel anything. Her blood, limps, and organs will be the first thing you see after you wake up.. Of course I will be gone after that, so long Tanjiro."
"He's not bluffing, I can sense his intention and power to do that. But if I surrender now what will I become? I will be demon in his stand.. I am afraid that more lifes will fall because of my thoughtless choice now."
Tanjiro's not wrong, he consider his choice very carefully, but to lost the person he loved right in front of his eyes now will be a nightmare to him after he wake up. But if he became a Demon, he will end up everyone else life sooner or later.. maybe included Kanao too.. and his sister, Nezuko. As he struggle with his choice, Muzan didn't wait for him to decide of course, He began to take control over Tanjiro.
"Wait, Muzan!"
As Tanjiro still hold off Muzan's power to take control from him, outside his inner consciousness, Nezuko began to run toward his brother.
"Brother!!"
"Ah, this is gonna be interesting." said Muzan with a grin in his face.
"You seriously dead now." said Tanjiro with all that hatred and anger toward Muzan.
"Technically, I am dead already you know? What you see now is just a remaining fragment that I plant inside you, with no probability to keep alive let alone taking full control over you.. It just manipulates you to become a demon.. But it can take several lives away in a glimpse of a moment by controlling your body in split seconds.. That one is not a lie, you can feel it too right?"
"Stop bullshitting!! YOU.."
".... What's this strange feeling?"
"!!!"
Tanjiro can feel his hands choking on someone and his tentacles-like weapon began to strike only his sister. Nor Sanemi or Giyuu can respond on time to that tentacle weapon, even though they can still save Kanao by cutting Tanjiro's hands.
"Shit, what happened?!" said Sanemi.
"No, Nezuko go away!" said Giyuu out loud.
But, it's too late the tentacle weapon strike toward Nezuko and.. it suddenly stopped. Without thinking too long, Giyuu moves toward Nezuko and manage to take her away from Tanjiro attack range. Tanjiro's not moving at all, while the others step back to a certain distance and stay alert.
"I.. am.. beyond help.. Please do me a favor.." said Tanjiro while maintaining his sanity.
They all were surprised that Tanjiro came back to him.. That's what they thought, even Inosuke and Zenitsu began to awake from their unsconciousness as they heard Tanjiro voices. Tanjiro began to move away from them, slowly walk away, while saying..
"Kill me.. the next time.. you guys meet me.."
Shocked by his favor, his friends began to ask him while chasing him.
"Wait! Stop joking Tanjiro! Why you have to do such a thing when Nezuko finally gets back to her normal state, have you lost your mind?!" shout Zenitsu.
"Tanjiro.. does the drug not effective enough?" thought Kanao.
While Inosuke, Giyuu, and Sanemi strike right away to Tanjiro, Nezuko feel powerless as she sit still, shocked by his brother request, along with tears in her eyes.
"You think we will let you get away with this!?" shout Sanemi.
"Stupid Tanjiro! This isn't you at all! Just stay still and face us properly you idiot!"
"Tanjiro! You don't have to do this!"
Tanjiro didn't say a thing, as he grabbed the nearest sword to him, which belongs to one of the corps he killed. He gripped it one-handed and began to slash through the ground.
"Demon Breath, First Form : Inferno."
A wall of lava began to rise from the ground, it's a bloody lava that will burn anything it touches to nothing. Shocked by the lava-wall they began to jump away from it while maintaining their breath. The lava-wall even made the oxygen around it vanished away, so they can't get near Tanjiro. The sword that he used to create the lava was broken immediately after he used his First Form. After Tanjiro left far away, the lava-wall vanished away immediately, normally it won't gone untill Tanjiro died but he could cancel it right away with his newly gained power of demon from Muzan.
"So he really beyond saving now.."
"The moment right before he uses his skill, right before he slashes the ground, had you guys seen his eyes?" said Kanao.
"I think its bloody red.. but the left one is still normal, just like before he turned to a demon." said Zenitsu.
"No, I think I understand what Kanao means."
Everyone wondered what Giyuu had to say with all of them gathered to Nezuko's spot. Nezuko still froze up and didn't say a thing. Zenitsu try to cheer her up but.. he still thought about Tanjiro's word back then. Inosuke angered by Tanjiro's cheeky behavior and decided to keep quiet for now, because he didn't know what exactly happened to Tanjiro.
"So, what is it that you want to talk about?" said Sanemi.
"Tanjiro right eye may become bloody red, but his left eye.. shed tears.. the expression on his half-face.." said Giyuu
"I thought it was the same expression.. when that Flame Pillar guy died in front of him." carry on Inosuke.
Everyone was shocked, even Nezuko began to respond to what they talked about.
"Just what happened to him actually, does any of you know the cause?"
"I think.. the drug may take some effect towards Tanjiro consciousness.. otherwise Nezuko and I must be killed back then.." said Kanao.
"We can't think straight with all this messiness, for now let's take care of anyone who lived.. if there is even one actually." said Sanemi.
"Ah, look there, some survived from Tanjiro's assault back then."
All of them were depressed with what happened to Tanjiro, they didn't know what exactly happened.. inside of him. Along with some people survived, they took their way to the Ubuyashiki mansion for now.
Seeing the same sunset glow as his brother, Nezuko couldn't help but think about his brother.. and soon she decided to master the sword under the same training his brother take to become a Demon Slayer Corps.. so this turn, she can saved his brother, that's what she thought. Meanwhile, Tanjiro keep moving from mountain to mountain, while he can maintain his sanity.
"I guess it's not long before I totally lost my sanity.. I begin to feel the blood-thirsty.. It's so hard to withstand it. I am thankful to Kanao's drug for now."
Tanjiro thinking back about what happened then before Nezuko almost died in his hand.
"I will become demon as you wish so.. Stop that tentacle right now, unless you want me to suicide right now." said Tanjiro. Muzan could feel his seriousness.. and didn't think Tanjiro could kill himself in this state.
"I don't know why but.. this kid doesn't seem to be lied about that.. I believe I can sense it.. about suicide thing he talked just now but, how actually.." thought Muzan.
"Never mind that, I achieved my goal so.. I will take his word. This is better than killing those two chicks anyway." thought Muzan.
"Okay then, I, as a fragment will merged with you and give you characteristic and power, just like a normal demon would. But, it stonger than usual.. because I am giving my parts to you.. not only blood.."
Tanjiro just keep quiet and didn't say a thing.
"I am really interested in what you will become.. Unfortunately, I can't see what will you become. So, I will enjoy watching you suffering.. from hell, Tanjiro." said Muzan calmly with a psycho grin on his faces.
Along with his laugh Muzan began to vanish from Tanjiro's inner soul and ask a favor to his friends back then.
"Fortunately, Muzan was pressed by my suicide attempt, if not for that Nezuko would be killed for sure.. I didn't even know if I can suicide but.. I thought the concept was somehow similiar to what I experienced before hand.. that fight with Lower Moon one Demon. I killed myself in dream and woke up but, in this case, if I killed myself in my inner soul, I should be dead along with Muzan.. But I can't take that risk because there is a possibility that he would still kill Nezuko with his remaining power while I am getting myself killed. I don't have many choices but I guess it's better than seeing my sister killed in front of me." thought Tanjiro.
"So, I am going to be killed by one of them.. If only I could kill myself now but.. the demon power wouldn't let me do that.. I am resistant to the sun but.. it still weakens me.. thought I can't be gone instantly like other demons usually died because of the sun, but I guess I still can die because of it. Unfortunately this demon's power hinders me to do die that way."
As he moves forward, Tanjiro's thorny road will soon be revealed in front of him.. whether he likes it or not.