Chapter Text
Kyojuro has always considered himself to have a strong sense of justice. When he was a young boy, just discovering his own strength, his mother had told him to use said strength to protect those not lucky enough to be gifted with the same strength as himself. And he had done that, his whole life.
Even after presenting as an omega at the tender age of thirteen, Kyojuro had taken up his blade again and beat his own body into submission in order to be strong enough to continue living his mother's wish. Everyone around him had been convinced he'd present as an alpha- his father was one, his father before that. He had all the early signs, they said, and would make a great alpha.
When he'd been training in the yard and suddenly dropped to the ground in a raging fever, those dreams were dashed. After his first, and very confusing, heat had ended, he was told by his father that he should just give up his hopes of being a Hashira. He did not want to be the flame Hashira for the title or the glory- he wanted to do it in order to be able to better the world and save as many people as he could.
Thankfully, the Demon Slayer Corps were non-discriminatory against those of an omegan backgroud, which was rare as a whole. Many people still thought that omegas should just remain home, barefoot and constantly pregnant. Kyojuro had worked his way up through blood, sweat and tears until he was summoned by Ubayashiki-sama in order to be offered the vacant Hashira position.
It was not recommended for any slayer to be on full-blown suppressants long-term due to it compromising your immune system on a constant basis and the mental instability it can cause. But, luckily, there were other options. Kyojuro had been taking low-dose suppressants for several years now. They did not suppress his nature, but instead lowered his scent output and made sure his heats came at scheduled intervals, for safety purposes.
He feels now, in this moment, the greatest sense of justice filling him from the inside out. He'd felt the immense pressure created in the air from the sheer power that the upper moon brought with him, and every maternal instinct he'd ever forced down was coming to the surface. He glanced back at young Kamado, laying behind him, bleeding and injured and clearly scared. He thought of the boar boy, the yellow-haired kid and Nezuko, the passengers of the train. His forgotten instincts rushed to the surface, leading to him lowering himself into a kneeled fighting stance when the dust cleared enough to see the demon who had struck the ground.
Upper Three. The kanji in the demon's eyes were clear, in a yellow pupil surrounded by fractured blue sclera. The demon was squatting low, one fist pressed into the earth. His skin was corpse-pale in the dark, black (or maybe blue?) lines of tattoos trailing along well-muscled skin. He looked human in form, which may have been even more frightening.
Before Kyojuro could even blink, the demon had shot forward to take aim. Not at him, but at Tanjiro. Before the thought has finished forming, Kyojuro had shifted and unleashed Flame Breathing, Second Form: Rising Scorching Sun, in order to slice the demon's arm clean in two. As soon as the sword left the skin of his arm, the demon vaults backwards, executing a series of flips to create distance between him and the Hashira.
As fast as the wound was created, it is sealed as the split arm snaps back together with a disgusting cracking sound. Most of the blood vanishes instantly, but the demon licks a few drops off his palm with a slightly pointed tongue. "That's a fine sword," it declares.
He sure can regenerate fast. So, this is an Upper Rank, Kyojuro thinks.
"I can't understand why you'd go after a wounded child first." Kyojuro snips, feeling irritated that Kamado had been the first target after being grievously injured.
The demon smiles, tauntingly. "He could get in the way of the conversation... between you and me."
Kyojuro feels his instincts rise further, disgusted at that being a 'good' reasoning for targeting an injured person. "What would you and I have to talk about? I've never met you before, but I already dislike you."
Upper Three leans forward a bit, seemingly interested. "Is that right? Well, I loathe weak humans, too. The sight of a weakling makes my very skin crawl."
Kyojuro tightens his stance, shifting his grip on his katana. "Then it looks like our senses of value are completely different."
The demon extends a hand outward. "Well, then I have a brilliant proposal for you. Why don't you become a demon, too?"
Kyojuro blinks once, a bit startled. "I will not."
The demon's eyes widen ever-so-slightly. "I can see your strength at just a glance- you're a Hashira, aren't you?" He looks way too gleeful asking that, and Kyojuro's sense of unease is growing by the second. "Your fighting spirit has been honed to near perfection. It's close to the realm of the highest."
"I'm the Flame Hashira, Rengoku Kyojuro."
The demon grins at him, fangs gleaming bright under the light of the moon. "I'm Akaza. Kyojuro... let me tell you why you can't enter the realm of the highest. It's because you're a human. Because you're going to grow old, and you're going to die." He pauses to extend a dark-tipped hand towards Kyojuro. "Become a demon, Kyojuro." He purrs his name almost seductively, making Kyojuro squirm a bit in discomfort. Maybe it had been a mistake to present his given name so easily. "Do that, and you can go on training for a hundred, two hundred, years. You can become stronger."
Kyojuro hears Tanjiro shifting slightly, his breathing still harsh with pain. His sense of justice and duty burns brighter with the need to protect the boy behind him. "Both becoming old and dying are part of the beauty of being human- it makes human life precious and noble. "Strength" isn't a word used just to describe the body. This boy isn't weak!" He exclaims, feeling passion building alongside his other current feelings. "Don't insult him. I'll repeat it as many times as it takes. You and I have different senses of value. No matter the reason, I will not become a demon!"
Akaza's eyelids lower slightly, seeming disappointed in his response. "I see." The demon shifts completely, the horrible pressure from before returning in a moment as the ground caves under one of Akaza's feet as he switches stances. "Technique development, destructive death... compass needle!"
Kyojuro tightens his stance one last time as the demon readies itself. "If you won't become a demon, I'll kill you." And before a breath can be taken, the demon has sprung.
~
After fighting from a distance for only a minute, Kyojuro realizes he will have to close the distance between them to have any kind of chance at survival. As he does so, he accepts that any hit at close-range will also have a large chance of crushing his own chances at winning.
He hears Kamado trying to get up, glaring at the boy out of the corner of his eye. "Don't move! If that wound re-opens, it will be fatal! Stay back, that's an order!" The boar-headed boy, Inosuke, is with Tanjiro now as well- another person he feels he must protect.
Akaza seems irritated at his momentary lack of attention. "Don't bother with that weakling, Kyojuro! Come on, give me your best shot!" Kyojuro lands a small hit, sending the demon back a few feet. "Concentrate on me!" He seems almost petulant, but Kyojuro doesn't have time to focus on that as they continue to meet again and again.
When the first proper hit on him sends Kyojuro flying back into the metal body of the Mugen train, he feels the pulsing pain like nothing before. He thinks he has at least one cracked rib and sweat begins to bead up across his skin as he tries to regain his controlled breathing.
Akaza eases a bit closer out of the trees. "Become a demon, Kyojuro. Fight me forever and get stronger together with me."
"I'll pass! Let me repeat it again: I don't like you!" Kyojuro drags himself back to his feet, feeling aches already forming. "I will not become a demon!" And he dashes back into the fray, without a second thought.
The next hit Kyojuro takes splits the skin above his left eye, pouring blood down his face. Every time he strikes off a limb, it is regrown instantly, before he can even try to use it to his advantage. He feels his energy sapping, more sweat pouring off him as he fights to stay alive and keep the demon's focus on him as opposed to anyone else.
The next hit brings the demon close, too close. Akaza's fist strikes his middle, definitely damaging some of Kyojuro's organs as he gasps and let's slip a small whimper of pain. Stronger scents are coming to him, he realizes distantly. His suppressants must be wearing off from the stress and the amount of sweat and blood he's losing. He can smell Kamado's sour panic, Inosuke's primal terror, and he can even smell the demon in front of him.
Low-level demons often smell of nothing but bloodlust. The Lower Moon demons he has personally encountered smell of one designation or another, usually alphas or betas, but not very clearly. This demon is an alpha, loud and clear. His scent is akin to a winter storm, intense and cold. He also smells of iron, like fresh blood and something entirely feral. Kyojuro feels his head reel slightly as scents press in on him at once. He smells his own distinct smell begin flooding out of him in a panicky swirl of pain and stress.
The demon punches towards him again, his fist meeting Kyojuro's eye- but he pulls the arm back before it fully crushes Kyojuro's eye underneath the lid. Akaza stumbles back, those unnerving eyes blinking rapidly. Something in the air changes, the crushing pressure lifting slightly.
The demon is seeming to hesitate, and Kyojuro realizes he must have smelled his omegan scent permeating the air. He'd had human opponents refuse to spar with him because of his second gender, but never had it impacted a fight with a demon before. He's furious. "Wha-" he pauses to cough, a bit of blood leaving the corner of his lips as he heaves "what- you draw the line at fighting omegas?"
Akaza tenses, shoulders pulling forward as if he's ashamed. "I can't."
Kyojuro doesn't give him the chance to continue if he was planning to, he braces himself to try and unleash one of his forms. As his third form is halfway completed, he sees the demon's leg kick forward to press into the middle of his thigh. He feels the bone snap clean through as it gives out on him, sending him careening down onto his good knee. He gasps again with the blinding pain that runs through his whole leg.
Akaza leans forward. "Rest, Kyojuro. Think about my offer and grow stronger." Rengoku is dragged forward by a hand grasping his uniform by the collar. He cries out as he's jostled with the movement. A blue-tipped hand rips out a chunk of Kyojuro's uniform that covers his neck, before he feels a press to a nerve in his neck, making him pass out suddenly.
The last thing he hears is rapidly retreating footsteps as well as smaller footsteps closing in. "Rengoku-san! Rengoku-san!!!"
~
The next thing he knows is light behind his eyelids, way too bright as his right eye peels open- his left seems to be covered. He sees Kocho above him, a serene smile on her face but relief in her purple eyes. "Welcome back, Rengoku-san! I thought it seemed as if you may wake today."
Kyojuro's head sinks further into the pillow, staring up at the ceiling. He had lived. But not because the demon was weak enough to defeat, but because his designation made the demon consider him weak enough to not consider killing.
Tears prick his eyes. I'm alive, I'm alive, I'm alive.