Male OC X Kimetsu No Yaiba / Demon Slayer

Upper Moons

[GREAT NEWS!]

[Isn't this great? I sulk for days because the manga had ended... (Kyojuro died TOO early T-T)... But now I can set my heart ablaze!]

No One's POV

Nakime plays her biwa and the fortress moves to her tune. Both Upper Moon Six arrive first. "Where's everyone else? Ha! They're such slowpokes!"

"Shut up, Daki. If you don't want to die here, you better behave." Gyuutaro grunts as he has to deal with his sister's idiocy.

Soon, Gyokko, Upper Moon Five emerges from the pot. "Great. What now? The last time we had a meeting is because a certain demon 'declared war' against Muzan-sama."

Upper Moon Four, Hantengu, creaks the door open. "A-a-are we in trouble?" His voice is shaky. "B-b-because we didn't kill that demon y-y-yet?"

Upper Moon Two, Doma, arrives at the scene with his 'happy' face. "Good to see you all again!~" He searches for a certain demon but couldn't find him. "Kokushibo, where's Akaza?"

"Don't know and don't care. If he's late, that's his own problem to deal with." Upper Moon One, Kokushibo, spoke from behind the closet.

"So, everyone had arrived..." The Upper Moons, except Kokushibo, look upwards and sees their leader, Muzan Kibutsuji doing some kind of chemical experiment.

"What do you mean, Muzan-sama? Akaza is not here yet." Gyokko says.

"He's dead." Muzan continues his experiment casually. Hearing the news, the Upper Moons fear what Muzan would do next. "When I eradicated the Lower Moons, I thought that you're more competent to eliminate anyone that I think of as an obstacle." He's angry. No doubt it. "Not only you still didn't manage to destroy Demon Slayer Corps, now, but there's also another demon going against me. You know too well who is his companion, isn't that right, Upper Two?" His words filled with venom.

"Someone I know too well? You mean... my otouto?" Doma scratches his cheek until it bleeds as he 'smiles'. "He accompanies someone? That's new. He doesn't want to make friends with anyone for ages but now he has one? Intersting~"

"I don't understand. If both of you are demons, why aren't you stay together unlike me and my nii-san? Both of you can be useful to Muzan-sama!" Daki directly said that to Doma.

"Hmm~ That's because he's obsessed over someone named 'Oreki'. I never saw this 'Oreki'. He would always talk or play all by himself and pretend as if that 'Oreki' is there with him. He doesn't want to make friends with others. He even ditched me countless times!" Doma slightly cries in despair.

"H-he t-talks to someone who doesn't e-exist? Scary!" Hantengu cowers in fear.

"Great. These siblings are both insane." Gyokko comments.

Kokushibo sighs in relief that his late brother wasn't insane like them.

"That's exactly what your brother called the demon he accompanied." Muzan interrupts while still experimenting. "The demon can shapeshift. But he possesses different Blood Demon Art each. He fooled Akaza's senses to think that he's human. The demon, no, he is another monster in disguise. From Akaza's vision that came to my mind, his fighting spirit is more suitable to be called killing intent. If you ever see an emotionless man that has golden hair with red tips, eliminate him. Dismissed."

Nakime plays her biwa as she teleports Muzan back to his lab, leaving the astonished Upper Moons. "That's... very helpful. Not many people have that kind of hair." Gyokko turns his head towards other Upper Moons.

"They could just dye their hair that way." Gyuutaro as negative per usual.

"We don't have another clue? Hey, ya thot! Give us more info about this 'Oreki' and your traitor brother!" Daki reveals her true mean side after Muzan left.

"Ne... you're so mean!" Doma cries comically.

"We don't have time for this drama. Tell us already!" Gyokko demands, totally fed up with his childlike manner.

"My otouto once told me that Oreki is an outcast with the nickname 'demon'. Oh! And my otouto is smart too! Too smart for his age! He almost stabs my eyes back then when we're still humans~"

"HOW COULD YOU SAID THAT SO CALMLY?!!" Daki shouts.

"He could use a knife that young? And almost killed you even though he's still human? I never thought such a child exist." Gyokko deadpanned. These siblings really are insane after all.

"He isn't bothered by the scent of our parent's blood. He inhales it as if he's familiar with it. He defeated the lowly demon that once tried to eat him. After he turned demon, he killed some humans but he eats other demons instead, saying that the humans he killed are...*mimics Katsuki* 'disgustingly weak arrogant creature'. Sadly, he left me after I became part of Twelve Demon Moons! Why does he mad at me?! Isn't it every demon's dream to become one?!" Doma let several teardrops fall.

"So, even if Muzan-sama kills you, he wouldn't care anyway." Gyuutaro points the left-out fact.

"Ne?!! That's too mean!"

While the others are having verbal fights, Kokushibo stays there silently, a few distances from the ruckus. His mind is elsewhere.

Emotionless face

Golden hair

Red hair tips

He knew one person who fit those descriptions perfectly. His mind replays their last fight where a blue skeletal monster appears from the boy. His eyes bleeding but filled with caged emotions.

'I think you're cool...' The boy frantically waves his hands in the air after he said that.

'I want to stay human!' The boy once said with full determination.

He grimaced. Kokushibo thinks that Doma's little brother is somehow responsible for turning Yoru into a demon. He knew very well that most demons would lose their memories like humans.

Yoriichi... no, he's not Yoru anymore. He's Oreki. A demon. A monster in disguise. A very dangerous one. They're not the same. Kokushibo tries to plant this thought into his mind as it will hinder his duty if he ever holds back.

But some memories start to resurface again.

Thick black smoke appears at their first encounter. After the smoke cleared, Yoru had fled away, leaving him confused.

Yoru gave thumbs up in front of his own mother's grave... like, seriously! Thumbs up? That's something he never expected.

Little Yoru spinning after Kokushibo tied his golden hair came to mind.

He can't do it. He can't forget Yoru.

"Looks like the only resolve is our rematch. It'll be the last of either one of us." Kokushibo whispers under his breath. Because his face is facing the wall, no one noticed his depressed face.