The Purpose Of My Existence

(A/N : I made this chapter to a certain Reader, also this is the last Chapter of the Demon Slayers ARC! right also pick 2 of his womens to join him going back in his world.

1. Kie Kamado

2. Shinobu Kocho

3. Tamayo

4. Kanae Kocho

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Mark and the demon Slayers arrived at the location where, Muzan is, many Slayers got tired for they were not monsters like the Pillars and Kagaya.

Mark told them to rest for a bit, especially those weak Slayers, but he'll make sure no one dies.

In a certain place where Muzan was staying, he saw Mark and the Slayers through the eyes of a low class demon, Muzan got his face pale, paler than he has now, he fears Mark more than anyone!

He gathered all of his demon pawns, to prepare to fight Mark and the Slayers, he knew running this them will be a failure!

Mark naturally noticed the demon eyeing them, but didn't kill it yet and let it look at them for a while.

After a few moments, he killed it swiftly and no one noticed, except for the Pillars,Kagaya and Tanjiro.

He stood in front of the Slayers and shouted " My Fellow Slayers! ready yourself! this is the last night you'll see a demon! we will exterminate them all! "

The Slayer screamed loudly, for their blood was boiling at his speech! Mark has this certain charisma that made them believe him!

Giyu eyes glints " They are coming! "

The other pillars nodded, the low ranked demo Slayers got nervous, they knew this was their last and the biggest battle they'll have in their lives!

Some of them gritted their teeths, this is what they were fighting for! they can finally avenge their fallen Family, Friends, Teachers and comareds from these demons!

Suddenly there were several flashing figures was dashing at them those figures were all Upper Moon Demons! and at the back at them were all the demons ever exist!

Those demons were numbered tens of thousands! The Pillars, Kagaya and Tanjiro and the rest smiled widely, they were eager to fight!

The low ranked Demon Slayers got scared, more than tens of thousands demons! yet they were just numbered a few hundreds!

Mark grinned widely he laughed " HAHAHA!! Now this is what I call challenging! Tanjiro! use your ability! "

Tanjiro nodded " Yes!! "

That goes without saying, Mark dashed toward the crowds of them laughing maniacly and Tanjiro also followed they're both using The Breath of the dragon third form! Dragon's Rage!!

They faces was filled with birth Marks! specially Mark who looked like a devil, right now, suddenly Mark used his Quirk! he never used it publicly but now he doesn't care! for he is exicited to Exterminate these demons!

Mark shouted " BURRNNNNN!!! HAHAHA "

With a single wave of his hands hundreds of demons got burned and died, the Demon Slayers got shocked not just them, the Pillars, Kagaya, Zenitsu, Inosuke, Yui and Kanao!

Kagaya " What is that power??!! Sensei never showed as that! "

The rest of them got their mouths agape, Shinobu chuckled and explain " Actually I know about that...he told me before, he doesn't want anyone to know of his ability so he hides it, but now it seems he doesn't care... in fact this was the first time I've seen him gets too much excited. "

Suddenly Tanjiro made a similar power he shouted " Explosion!! "

Boom! BOOOOM!!

A burst of Explosion happened, and it at least killed a several hundreds of demons! Tanjiro sweats while using it, it takes too much stamina! he thought ' I can probably use it a few times... '

Again they got shocked to the scene, in front them they never knew powers like those existed! but they didn't care anymore and got more exicited and they screamed " YEAHHH!!! LETS GO EXTERMINATE THIS F.U.C.K.I.N.G DEMONS!! "

All of the Slayers blood was boiling, the dashed in front with their faster speed! as they saw a demon they'd kill it hastily, they felt stronger at this time.

The Pillars also moved, the battle lasted a few hours, all of the demons got killed, The Pillars killed the Upper Moon Demons with ease, heck Sanemi even killed the Upper Moon Demon One by himself.

He boasted but got ignored, which he got pissed, Tanjiro got exhausted, he used too much of his Devil Fruit Ability, it was stamina consuming! but he was satisfied! he killed more than a thousand demons!

The Demon Slayers screamed of victory! they won! humanity one! most of them cried, they finally avenge their Family and Friends.

Now as for the last one, it was Muzan! Mark caught him before he could escape, Mark sliced his limbs, normal it wouldn't heal for a week like Yushiro, but he was the Founder of the Demons! he regeneration is perverted, he'll probably heal for an hour.

Mark dragged Muzan in front of the Slayers, the Slayers looked at Muzan with Rage as if their looks can kill.

Mark looked at Kagaya " He's yours. "

Kagaya bowed at Mark and said " I'm in your debt forever, thank you for this opportunity Sensei! "

Mark just waves his hands " Drop it, you don't need to also don't call me Sensei anymore. "

Kagaya smiled and bowed for the last time, he looked at the crippled Muzan, he gritted his teeth and viens appeared all-over his head.

Kagaya shouted " If is wasn't for you! our family wouldn't suffer! we wouldn't have been labeled as the family of Demons! do you know how many family members got burned because of you?! they were innocent! this time I'm gonna end you! all my life I've been waiting for this moment! at first I'm satisfied of others killing you! but I never thought I'd be the person to kill you! "

Muzan " Kagaya.... you'll never know how I feel... ever since I was born death is already chasing me! in my mother's w.o.m.b my heart has been constantly stopping yet I fought! when I was born I was labeled as dead! when I was to be burned I cried! I keep fight till the end Kagaya! you will NEVER feel how I f- "

Kagaya didn't listen to his nonsense anymore and Killed him by slashing his multiple brains and hearts.

Kagaya cried and said " It's finally the end... "

The Demon Slayers- no the people is now celebrating they have achieved victory! there is a few heavy Injured and a several minor injuries but no one died!

Mark thought ' It's refreshing... ' he smiled, he never thought he could smile like this again.

It was thanks to the people around him, especially his womens.

( Demon Slayer ARC END- )

Yeah there will be and aftermath chapter after this.