Male OC X Kimetsu No Yaiba / Demon Slayer

Brothers

Senjuro's POV

When my father told me about our ancestors being Demon Slayers, I can't help but be inspired. At the same time, I'm a little bit scared. That means one day I have to face those scary demons too.

He always tells me his experiences during his days as the Flame Pillar before I sleep. Sometimes, I've got too scared that my Kyojuro Nii-san and Obanai Nii-san have to comfort me until I fall asleep. I know Obanai is not my biological brother, but I still look up to him as a brotherly figure.

When I've reached three years old, they always bring me to their sword practice. Father would stay home and take care of mother while we're away. Kyojuro niisan and Obanai niisan moves so fast! Their swordsmanship is awesome!

"Woah! Those moves are awesome! You both are so strong!" I compliment them but both shook their heads.

"No, we're not even close to Yoru-Kun's strength and speed." Obanai niisan sit down to rest for a while. I run to get closer to them.

"Senjuro-Kun, remember that one-time father mentioned I have an older twin brother named Yoru?"

"Yes. But he never reveals where he is now or what happened to him."

"Well... oniichan... I mean, Yoru niisan is... full of surprises!"

"Huh? Surprises?" I don't really understand what Kyojuro niisan means.

"He... already works as an official Demon Slayer for the Demon Slayer Corps since you're just a few weeks old. He's ten at that time. Then... the most shocking part is... he earned the Pillar rank in just five days! He even unlocked his Demon Slayer Mark!" Kyojuro niisan said with enthusiasm.

My mouth is wide open. "Eeeehh?!! Really?!! That sounds exactly like the Twilight Pillar story father told me!"

"That's because Yoru-Kun IS the Twilight Pillar. The first one in the history." Obanai interrupts.

".....EEEEEHHH?!!"

"PFFT! Hahahaha! Your reaction is cute!"

"K...Kyojuro niisan!"

"Ahahahaha! Sorry, sorry." Kyojuro niisan pats my head.

"Why father never told me that? And why Yoru niisan is a Twilight Pillar, not a Flame Pillar?"

"Because he didn't want you to be upset. When Yoru niisan was about to go on his first mission, you grabbed his sock and said your first word. He had to go so he gave you to me and you started to cry. He instructed me to make an emotionless face to copy him and it did the trick. He may seem emotionless, but I can tell that he's heartbroken to leave you behind."

Well, that's embarrassing.

"As for the second question, that's because his fighting style is... brutal. Don't ask further than that. You'll get nightmares."

Huh? I'll get nightmares? Is he scary?

"It has been three years since Yoru-Kun left us. We would train like crazy every day to get closer to his level. We have to complete our daily training or Yoru-Kun won't be happy." I see Obanai niisan shivers. Is he cold or something?

"Kyojuro niisan, Obanai niisan, when will Yoru niisan return?"

"He... we don't know..." Obanai niisan trails off.

"I'm right here." An unknown shadowy figure spoke behind Kyojuro niisan and Obanai niisan.

"AAAAAAAAAAAAAAAHHHHH!!!"

...

Yoru's POV