A Good Liar

Prologue

Reinforcement

After the great battle between Kibutsuji Muzan and his subordinates against the Demon Slayers, the infamous, ruthless and cold man Muzan, successfully fleed the compact grasps of the Demon Slayers. Ever since they retrieved back from the heavy pressured infinite fortress of the latter to the crust of the splendid paradise called Earth. He wasn't entirely vanquished by the organization just yet for how fortunate the man was able to shift himself out of the said organization.

After two years, Muzan had self rebooted, back to square one. Initiating scheme to recreate another batch of "trustful" subordinates. The moment he recouped his constant ability to devour humans once again with ease, the acceleration of power and strength has smoothly revived in the core of his inhuman body.

He planned to demonize a newly turned pillar. Who seemed very determined in eliminating the latter two years ago and counting. It was none other than the Breath of the Sun User, Kamado Tanjirou. For the "man", Tanjirou would be a great threat to his dear comrades for the lad was held upon the title of being the current strongest demon hunter pillar in the organization.

Before he could temporarily revamp Tanjirou into one of his subordinate, the man created a diversion that served to be an obstruction to follow his plan according by evolving a hopeless samurai into an unassailable demon. Manipulating the distraction to weaken the target to further accomplish his desires.

The said demon devoured countless horde of humans resulting for further improvement and development to his physical strength and other power related components of a demon. The exact same situation that the expected target following by an unexpected partner rushing towards the demon's area of position. 

The scheme went accordingly as the demon accomplished his task at hand to weaken the burden while ensuring their consciousness to be followed by the control of his master. There was no way to defeat an invincible opponent for the very first time. Surely, the pillars attempted their very best to eliminate their enemy, but it seemed that this demon entirely was a great obstruction for a purpose.

Muzan, commanded the demon to multiply their horde and devour humans even more. While he goes finally accomplishing his main plan. Turning this pillar into his new right hand, a partner.

He proceeded to Tanjirou, which was protectively laying beside the unconscious Kanao while tightly embraced himself around the girl. He wished to morph Kanao to a potential demon as well, but she didn't achievrf Muzan's priority limit just yet, Tanjirou is already incomparable.

Muzan's fortune finally reached beyond, whilst Tanjirou held Kanao tightly glaring intently at Muzan. Gritted his teeth in pure antagonism, oh how he wished to terminate Muzan in the moment, but luck wasn't on his side. His body couldn't tolerate anymore due to the immense pain and exhaustion the recent battle had offered him. So he remained on Kanao's side as the girl was recovering by reposing.

Extending his hand towards the boy before him, he scoffed negatively and glared pathetically at him. As if the boy was somewhat near his glorious victory.

"Do you want a hand?" He asked deviously.

The boy was showing his purest anger and hatred towards the demon leader. Sending overwhelming pressure and heat up until the man's silky and curly black hair. Albeit weakened and trapped, the boy still managed to give off something powerful with a short glance.

Tightening his grip around the girl's unconscious body protectively, he yelled bravely to the man stood before him.

"I don't need your aid! If my power couldn't have improved years ago, I could've killed you in an instant without delays!"

"But look before me, I'm still a living perfect man. There's no point battling anymore. You're weakened, you have no other choice but to seek for help. But no one's approaching, so you're left here helpless." Muzan said and kneeled down in seiza.

Looking angrily towards Muzan, he gritted his molars tightly and hardly almost cracking his own teeth. He snarled under his breath silently. Just like a lion whose ready to attack its enemy in a moment.

Smirking in devious satisfaction across his pale white skin, he said at his gentle and manly voice he possess.

"I could help you. If you'll become my subordinate, your comrades, especially her, will be saved. I will spare their lives, after when you join me in the greatest paradise."

Tanjirou shook his head in refusal. He doesn't want to become a monster like him.

"Boy, if you won't join, their lives will go to waste. They'll die instantly. All the weak people you wanted to protect, will just waste their lives. You became a demon slayer because you wanted to turn your sister back into human and protect people, right? Well, let's reverse that. Become a demon, to protect them. If you refused once again, say goodbye to them." Muzan said in false sorry.

"Even her, your current fiancee, right? Will die this instant if you deny. Do you want that to happen?" Muzan said.

Tanjirou looked at Muzan with full hatred. He didn't want to turn into a demon, but he didn't want Kanao to die, as well as everybody else. He knew how powerful this "man" is. The former strongest demon slayer travelled to eternal paradise hundreds of years ago whom closely into eliminating the latter.

Well, he had no choice. He didn't want to waste everybody's precious lives. He didn't want them to die mercilessly. Even if it cost his humanity, he wouldn't dare kill everyone for his sake. Then, he has to become one.

He cried and looked hopelessly at Kanao, who was still unconscious. He smiled for the last time and kissed her forehead.

"Kanao, if you ever hear this, don't worry about me. I'll be in good condition. Just protect everyone for me until I get back home. I love you. I always do." He whispered and laid her properly on the ground.

He stood weakly and sheathed his sword, he looked at Muzan and dashed forward. Even before Tanjirou could slash him, Muzan has stabbed his chest. Muzan's hand went through his stomach and dropped his blade.

"You couldn't do anything, right? It was correct to agree with me. You choose very well. Now then, you shall receive most of my blood and become stronger for me. Then, we'll conquer the sun together." Muzan said and sent most of his blood to Tanjirou.

Now starts his new life, with much stronger horde and reinforcement.

It's also the start of the demon hunter's change in their lifestyle! A new arc has begun! (Jk)