Chapter Text
Kokushibo stared at the little book in his hands. The one that had fallen to the ground beside that gods-damned flute.
Kokushibo did not look at his brother’s body, did not acknowledge the blood that was seeping into the earth and staining the soil deep crimson.
He couldn’t tear his eyes away from the book. It was a journal, written in Yoriichi’s neat, elegant handwriting and Kokushibo knew he shouldn’t have read it, he knew he shouldn’t have cared.
He’d been stupid enough to think it could contain notes on demons, or information about Muzan-sama. And upon realising what it really was, he’d cemented his grief stupidity and kept reading.
And now, now he didn’t know what to do with this–this grenade that he was holding in his hands.
Because that book held everything. Every single thing Yoriichi had ever done or been through was written in this little book and Kokushibo had read all of it.
Everything Michikatsu had been too blind to see, too busy to notice, too fucking jealous to ask about.
Yoriichi’s banishment from the Demon Slayer Corps. Kokushibo’s blood boiled at the knowledge of how they’d treated his twin.
His failure to kill Kibutsuji.
His wife and child, the sister and niece or nephew Kokushibo hadn’t even known he’d had. Whose memory Kokushibo had stomped on by joining Muzan.
The worst was what wasn’t there. Every accomplishment, every good thing Yoriichi had ever done, that Kokushibo could ever remember him doing. None of it had made it into this book.
His little brother’s self-loathing was etched into every page.
Why? Why had Yoriichi thought so little of himself? How could he not see all the good he’d done?
He rested his hand on the ground and recoiled when he touched something wet. He looked down at his hand and saw that it was slick with blood. Yoriichi’s blood.
His brother’s blood.
Had Kokushibo ever told him that he did good?
Had anyone?
He looked back down at the book. And found that he couldn’t stand the sight of it anymore.
With all his demonic strength he flung it away from him.
His eyes finally fell on his brother’s corpse, his once crimson hair and eyes just like his, now white with age and cataracts, those eyes that stared blankly up at him. Then on the broken flute, now drenched in blood.
And something deep inside Kokushibo just… shattered.
He fell to his knees and screamed.
What have I done?
Sobs wracked his frame and he clutched both that book and that flute to his chest as he screamed into the night.
What have I done?!
He barely registered the position of the moon in the sky, hanging low over the horizon, as he continued to cry.
The sun is coming, his instincts screamed at him.
Let it come. Kokushibo thought viciously. Let it fucking come!
He suddenly felt something warm wrap around him, pulling him out of the depths of his grief. It reminded him vaguely of standing in the sun when he was still human and for a moment he wondered if the sun was already rising.
But no, it was still pitch black around him, though the sky was steadily gaining a purple hue in the distance.
Kokushibo looked back at his brother’s remains and forced himself to stand. He moved to one of the few trees that grew in the area on shaking legs, before he knelt down and started to dig.
It didn’t take long, and when he was done, he moved back to his brother’s corpse and gently lifted him up and carried him to the freshly dug grave.
By the time Kokushibo had buried his twin the sun was nearly peeking over the horizon and Kokushibo ran from its rays like a coward, the small flute clutched in his hand.
He made it to a small cave just as the light reached across the ground.
He looked back down at the flute he was still holding in his hand and felt the tears sting his eyes once more.
I’m so sorry brother. Please forgive me.
His breath hitched as he bit back a sob and his fingers curled around the little instrument.
I’m sorry.
How could he ever make this right?
He remembered his brother’s journal. The raw grief that had bled into the pages as he wrote of his wife’s and unborn child’s deaths. The water damage where Yoriichi’s tears had stained the paper.
He’d thought his twin had joined the demon slayer corps for no other reason than to protect others. It had been such a Yoriichi thing to do that Michikatsu hadn’t thought twice about it.
He was such a fool.
Yoriichi had wanted – not revenge, that wasn’t like him – but justice, for his family.
“I can’t undo what I’ve done.” Kokushibo said quietly. “I can never even begin to atone for the pain I’ve caused, especially to you, brother.” He looked down at the flute again. “But justice… justice I can give you.”
And he knew exactly where to start.
Muzan Kibutsuji, your days are numbered. He thought savagely.