The Tenth Pillar. (Kimetsu No Yaiba X OC)

The Kamado Siblings

It's early morning and the sun holds no redemption for the tenth pillar.

As he woke up he could hear everything around him. The birds chirping. The wind blowing and the leaves dancing around with the soft breeze.

The raven haired boy took a deep breath. He could feel the presence of Aoi inside the estate, Mitsuri was there too, Sumi, Kiyo and Naho were helping the first.

He could feel their presence. The Reiastu they release was strong. The breathing techniques could be a factor in the growth of the Reiatsu. Hiiro took deep breaths, if he can't get out of the full focus breath, he'll began to leak his Reiatsu and the pressure could get so strong that all of the girls inside the estate could die from it.

He remembered Byakuya-sensei words and a memory came to his mind.

"What the Demon Slayers call Full Focus Breathing is just absorbing the Reiryoku and transmuting it to Reiatsu" The cold swordsman explained with his usual seriousness. He was currently under training with the Kuchiki clan head "We, who can manipulate Reiatsu as we please, do not need of the breathing techniques."

A swift attack came from the jet black haired shinigami. Hiiro evaded the wooden sword and launched a three strike counterattack. The noble samurai parried with ease each one of the flawless impacts.

"You've improved. That I recognize, but..." he began to barrage the young swordsman with lightning fast attacks, the golden eyed boy barely managed to block the furious assault from the Kuchiki.

When his sensei performed a more violent barrage combining the Shunpo into his attacks his apprentice fell to the ground, he took three hits, one to his legs, one to his ribs and the final blow to his head.

"It doesn't matter how much you improve. If you can't master the technique all your efforts will be in vain." he stated with a dry tone. Even though he showed calm and coldness like ever, he was impressed and proud of his apprentice.

In just six months he showed a colossal growth, the first day of training he didn't endure more than ten hits and just a bunch of seconds against him.

But now he could defend a full speed barrage of attacks. His golden eyes can see the sword of the Kuchiki, but... he still can't discover the secrets of the shunpo. Such a shame.

"We, shinigamis see no use in what you are trying to achieve. Trying to combine two styles of Swordsmanship, the Reiatsu control and the breathing techniques, that's something we can't accept."

He stared at the raven haired boy.

"But that doesn't mean that I'm not looking forward to the results of this training."

Hiiro smiled big and wide, a cocky grin appeared on his face. He began to chuckle.

"Even the great Byakuya Kuchiki can feel pride of his apprentice" the boy continued to laugh. The shinigami got closer and gave the boy a little bonk on his head.

"Stop talking nonsense." After a moment of reflection he continued "But certainly, I feel a little proud of you. Your discipline and hard work is paying off."

The smile on his apprentice widen as he heard those words.

"Now. Don't you have another lesson to attend?" The jet black haired shinigami inquired with his usual politeness.

"Oh yeah, Sneaky-sensei should arrive anytime so—" the boy received another bonk on his head.

"Who are you calling Sneaky!" A girl shouted while the boy rolled in the ground fron the pain.