"Set your heart ablaze."
Those 4 little words changed the course of Kagami's life forever. Four words that have separate meanings from one another if taken apart, but placed together showed the confidence, courage, and purity of a man who sacrificed himself to save everyone around him. That man was... Kyojuro Rengoku.
In the darkness of her eyelids, in between dreams and nightmares that plagued her in the dead of night and in bright sunlight, and the void that had filled her heart, were the images of Mr. Rengoku's dying words and last fleeting breath. The adoration and kindness in his wide smile never left even as his eyes took one last glance to the sun before falling to the ground. He had grown quiet for the last time happy and in content. He was... proud of them all, and believed they could become the next Hashira. Set your heart ablaze were the words he said to encourage them to continue fighting through the pain and protect those that need to be protected.
For a long time, for what felt like a million years, Kagami fell into a deep depression.
The first few days she hadn't been able to stop crying. All she could see was Mr. Rengoku dying over, over, and over again in her head. She saw him fighting a fruitless battle. She saw his chest get pierced by the fist of Upper Rank Three. She saw him unleash the most powerful moves he's ever produced... and it still wasn't enough to defeat him. Although, his mind was never set on ending the demon. It was always on protecting her, Tanjiro, and all the others trapped in the darkness of the forest standing in the middle of nowhere. Then, she didn't know when but she had run out of tears to fall. Her eyes lingered on mindless objects and it took everything she had to just take a singular bite of food.
"Mr. Rengoku," She whimpered staring into the floorboards of the Butterfly Mansion. They had been transported there by the kakushi, but not that she wanted them to.
She groveled at the ground, her hands clenching the hardened mud underneath her body, and fought them when she felt hands grab at her arms and shoulders. Screaming, wailing, and resisting with every last bit of energy she had, Kagami wouldn't let them take her away from the body of Mr. Rengoku. Tears like non-other poured down her face seeing his completely lifeless corpse kneeling toward the sun getting further and further away from her. "Big bro! Big bro! Please come back!" She continued to sob stretching out a hand to him before being taken away... forever.
Kagami laid almost like a corpse in bed, turned over from everyone and staring straight into nothing. Her hand laid limp falling off the edge of her bed. She blindly took the orders of Aoi to eat, drink, and sleep but... everything felt meaningless. The point of living fell on her deaf ears.
That was until Tanjiro reminded her of what Mr. Rengoku wanted them to do. And, just like that, the sun that had been hiding behind gray curtains sprayed light on her shriveled heart. It fluttered and ached but she stared at him in gratitude. She'd almost forgotten what he told them and what he wanted them to do. He wanted, needed, them to visit his family. They're going... to visit the Rengokus.
A small boy of 8 or 10 walked the streets of Asakusa, Tokyo. He gained none and no one's attention. It wasn't unusual for someone of his age and stature to be walking the streets on their lonesome. He had become quite well-known for being quiet, mysterious, but also humble and courteous. He frequented the Iwawado Bookstore and took an interest in the many books on the subject of indigenous and native plants of Japan. So much so that the owner of the bookstore became familiar with the boy and let him carry out books without the need to check them out. He'd simply look up, gaze at who rung the small bell by the door, and go back to the comforts of his novel letting the boy browse wherever and however he wished.
After selecting a particular book he hadn't seen or read before, the boy continued his silent trek back to his home. Once again, no one batted an eye or simply cared for his existence. Only another boy in particular, who seemed just a few years older, did a double-take. He stopped in his walk and stared at the small boy as he kept his stride, not faltering or hesitating in his step. The small boy wasn't bothered; if it had been a truly alarming situation, it would've been dealt with instantly.
Back at his home, the small boy's parents were having guests over. They spoke very well of him and how he could run the business someday. Except the small boy suffered from a rare skin disease that burns in the sunlight. He could only leave the house during the night and extremely cloudy days. His father was going to develop a miracle elixir for him, but the small boy knew it cannot be done without... the flower.
Bookmarking the page he had been lingering on, the small boy didn't flinch when the double doors to the balcony outside of his room swung open. They slammed harshly against the wooden frame, bringing in a light yet strong breeze with it, and nearly bounced back towards the doorway when a body in the center stopped it from doing so. Kneeling with one fist planted against the ground, head bowed deeply, was a demon covered in thick blue lines of tattoos, red hair, and yellow irises with a familiar kanji inscribed.
"Reporting in as you requested... Lord Muzan," The demon spoke.
Turning his head, the small boy gazed at Upper Rank 3, Akaza. The light blue eyes and emotionless, faded expression he had taken in the form of the boy instantly snapped away. Veins popped out of his face, fangs ticked his lower lip, and his eyes turned a startling plum red. The expressionless gaze fell away into one of malice. His thin-lipped mouth quirked downward slightly. "Were you able to find what I asked for?" His voice deep and raspy quietly bellowed out.
"I looked into it, but came up empty-handed. I couldn't find the Blue Spider Lily," Akaza started to explain much to Kibutsuji's displeasure, "There wasn't even a trace of its existence."
Kibutsuji stayed quiet for a moment. "And?"
"I will try to live up to your expectations. Forgive my unworthy efforts." Akaza lifted himself slightly from the ground and even sounded a bit proud when he mentioned, "But as you ordered, I was able to eliminate one of the Hashira. Rest easy knowing that much."
The displeasure in the core of Kibutsuji grew to a large, rampaging fire.
Turning from the bookshelf covering an entire wall of his filth, human room, Kibutsuji settled his slit-eye, crimson red gaze of venom onto Upper Rank Three. "It seems like you have the wrong idea about how things work here, Akaza. I'm curious," He scowled quietly and softly then lifted a long-nailed finger.
A powerful force spewed out from the tip and slammed hard into the demon. All the surrounding windows cracked like spider-webs, the wooden walls of the door and balcony railing behind creaked in protest harshly, and the demon winced and flinched like a feeble insect. All the veins in the demon's body began to pop out into the surface all at one time glowing a dark, sickly color. He could tell the demon was trying to keep his composure. Settling his wide-eye look of terror on the ground as a waterfall of blood spilled from his mouth, Akaza didn't dare to speak further.
"Did you expect praise? All you did was dispose of a mere cockroach. A demon beating a human is an underwhelming conclusion. What I want is for the Demon Slayer Corps to be wiped out," Kibutsuji's cold, taunting voice bellowed throughout the room without the single raise of his voice. It held no remorse or mercy watching the demon shudder in either pain or fear. He disgustingly reeked of it. "Squeeze the life out of every last one of them, and never let another one enter my line of sight again. It's hardly a complicated task, and yet I am still waiting for it to happen. Now, what do you make of that?"
He started ripping pages of his book into tiny pieces before entirely ripping the book in half. His anger and fury grew like non-other and his small hands clenched and crinkled the hardcover into ash. "You return here boasting of your infantile triumph over a Hashira. All the while, four other Demon Slayers survived the confrontation. Why did you not kill them when you had the chance? And after I made a point of sending you to that location because you happened to be nearby. Akaza... Akaza... Akaza... Akaza!" With each spoken word of his name, the demon bled more from his eyes, ears, and mouth, trying to keep the crimson red substance from spilling out in waves and whimpers from falling further.
"You have disappointed me so," He growled keeping his eyes steady and firm on the demon's head. "To think you have suffered a blow by someone who isn't even a Hashira. How far you have fallen, Upper Three." Turning to the bookshelf, and grabbing a book nonchalantly, Kibutsuji concluded, finally leveling his voice back down, "You're dismissed."
He felt the disappearance of who was supposed to be one of his strongest demons and turned back into the innocent child disguise he wore once again.
"YOU COWARD!"
The voice of the Demon Slayer with the hanafuda earrings pierced his head. Akaza flung the Demon Slayer sword that was once embedded in his back to the trunk of a tree. He stared at it then clenched his fists. The rage and fury he contained inside of himself after facing the wrath of Lord Muzan snapped. His eyes popped wide open, felt the energy flare in his core and throughout his body, and roared out into the sky! At a speed that was faster than light, he began to jab both fists into the Demon Slayer sword over and over again. He watched it chip away bit by bit to the sound of his yelling and screaming.
"YOU COWARD!"
His face, that ugly Demon Slayer's face, was all he could see and the whiny voice of calling him a coward made him even angrier! He wasn't running from him! He was running away from the sun! Why would that human think he was afraid of him?! Ridiculous!
"YOU COWAAAARD!"
"AAAH!" He bellowed out letting the sword explode into thousand of tiny, metal pieces.
Akaza's fists shook at his side, the snarl tightened on his lips, and his entire body trembled with the thirst for revenge. "Make no mistake. I'll remember your face, and when we meet again, I'm going to savor tearing you limb from limb!"