Chapter Text
Rengoku was relieved that Kamado had taken control of his breathing and stopped the bleeding in his stomach. “Nice work, Young Kamado!”, Rengoku beamed, “You’re one step closer to becoming a Hashira!” He smiled down at the young slayer until he felt a chill run up his spine. A smothering demonic aura filled Rengoku’s senses and the area of the train crash. His hand flew to his hip as he spun around, searching for the presence of the demon.
The Flame Hashira’s fiery eyes grazed over the figure that was the demon. He stared into the magenta eyes whose pupils stated, ‘Upper Three’. The demon flexed his huge biceps and slowly sauntered over to Rengoku. He cackled, showing many sharp teeth while extending his red and green claws. “Well, aren’t you a cutie? You must be a Hashira, you look strong, pretty boy!” the demon teased, “My name is Tengen. How do you call yourself, slayer? I must know!” Rengoku watched in disgust as Tengen licked his lips and slightly salivated at the possibility of battle. The blond steeled himself and gave a response to the creature before him, “I am Kyojuro Rengoku, the Flame Hashira.”
“Kyojuro? What a flashy name! I’ll be sure to remember it after I kill you. Be prepared, little slayer, as I’m going to end your life with flair!” Tengen laughed, settling into a fighting stance.
Rengoku gripped his katana and charged the demon, aiming for his neck. Before his sword could connect, Tengen vanished from the slayer’s sight. He swiftly turned around and saw him heading straight towards Kamado. Rengoku quickly scurried in front of the wounded teenager and slashed at the demon, whose claws met with his blade. Tengen jumped back and giggled, “I guess I can proceed with my orders later! I’ll just have to get through to you first, Kyojuro. I hope this won’t be a waste of my time!” Rengoku stared the demon down yet again, thoughts running in his mind. Why would he go for a wounded person? What orders is he going on about?
Rengoku started slashing his Flame Breathing forms at his opponent, barely getting close to his neck. The demon charged at the slayer, holding kunai in both his hands while murmuring something under his breath. “Blood Demon Art, Shrills of the Dead!” Tengen shrieked at the top of his lungs, causing Rengoku’s eardrums to burst. He clutched his head while blood pooled from his ears. Rengoku steadied his breathing and held his sword up, despite the temporary loss of hearing.
Tengen’s kunai clashed with Rengoku’s katana, causing sparks to fly in the air. Slowly, the blond man could hear the clanging of metal again as the ringing in his ears faded. “Rengoku-san!” Tanjiro yelled, worried for his new teacher and friend. The Flame Hashira looked over his shoulder and shouted back at him, “Stay back! That’s an order!” Rengoku swiftly focused back onto his opponent as he murmured something yet again, “Blood Demon Art, Choir of a Doomed Past.” An E-flat major chord ripped through Tengen’s throat, louder than the highest forte. Rengoku cursed and thought, it seems I will be deafer than I usually am after this battle! The demon continued to sing beautiful notes and chords in his face. Rengoku was confused, as he started to sob and shake violently. He felt warm and fuzzy as his vision started to blur.
The voices of people he knew rang through his mind, screaming his name. A magenta mist gathered around his eyes, showing his complete influence under the Blood Demon Art Tengen was using. Rengoku hallucinated, looking around himself, clearly unaware of his surroundings. He started to see things that weren’t there before, the battleground before him shifting to look like his estate. Was this another dream? It didn’t matter if it was or not, as there was a demon in front of him, threatening the lives of a little over 200 people. Tengen grabbed the slayer’s hair and forced him to meet his gaze. Rengoku’s hazy eyes still wandered around as the demon continued to hum. Rengoku dropped his Nichirin blade to the ground with a clang and clutched at the large, clawed hand fisting in his gold locks. The Flame Hashira was confused. “Why am I here? Where’s the demon?”, he murmured. Rengoku’s eyes finally met with the demon’s own in front of him, only to have the slayer recognize him as his father, Shinjuro Rengoku. “Father! Ah, please, would you release me?” The slayer smiled softly. Tengen pricked his claws into Rengoku’s skull, grinning wildly at the hallucinatory effect his Blood Demon Art had on the slayer.
Tengen leaned towards Rengoku and hummed in his ear. He began to sing the lyrics of his siren song, luring his prey to the ocean, “Why would you come here? Don’t you understand that you’re not worthy of being a Hashira? No matter what you do, you will still amount to nothing. You’re worthless, Kyojuro…Absolutely worthless…” Tears welled in Rengoku’s eyes as he struggled in the demon’s grip. It wasn’t uncommon for Tengen to play with his prey before feeding. He was about to shove a kunai in the slayer’s neck before Rengoku broke down and trembled in his opponent’s grasp. “Please, Father! You must have mercy on me! I train until the blisters in my hands explode! You were the one who gave me a sword once I could start walking! I learned the Flame Breathing Techniques at five years old! You mustn’t see me as worthless; I try so hard… I’m trying so hard to make you proud and keep the Rengoku Family flame burning!”
Tengen froze, and his kunai clattered to the ground. Rengoku was released from the demon’s hold and fell onto his hands and knees, the mist from around his eyes dissipating. He looked up a little hazy to see the demon he was originally facing. He must have used a Blood Demon Art to personally attack me. The Flame Hashira picked up his discarded katana and stood up to face his opponent. However, confusion only grew in him as the demon before him clutched his head and growled. Tengen glanced toward the horizon and realized the sun was bound to rise. He started to run away with the Flame Hashira sprinting after him. Should Rengoku be chasing after a demon? No. However, he did not want the Upper Moon to harm any more humans and was determined to end his reign of terror. He followed the demon into the nearby woods, shouting after him. “Stop it, Upper Three! I am not finished with you!” Rengoku roared, quickly catching up to Tengen. The Flame Hashira tackled the demon and looked into his magenta eyes. He looked deeper at the kanji engraved into his irises and noticed them dilating like a human’s pupils. Tiny tears formed in his eyes as they glazed over, squeezing shut in frustration. Tengen thrashed and growled at the slayer as he tried to slice his head off. “Leave me alone! Go away! I don’t want to remember!” A guttural roar ripped through the demon’s throat, causing Rengoku to cover his ears.
“Why are you acting like this suddenly? What is happening with you?” Rengoku asked, keeping his blade mere centimeters away from his opponent's neck. Tengen shivered as the sun breached the horizon, his body screaming at him to hide further into the shadows. His sharp teeth chattered, and his hands trembled. Rengoku saw the sun’s rays reaching them slowly, and the demon watched them with fear in his eyes, soft whimpers and growls escaping his lips. Tengen tried to shimmy away from the light, but the sun’s rays mixed with Rengoku’s strength kept him in his place. “What do you not want to remember? Tell me.” Rengoku pried at his opponent, pushing his blade closer to his neck. Tears freely streamed down Tengen’s cheeks as the slayer hit his weakness. “Why! Why would you bring the past back up on me? This was incredibly unflashy of you! If the sun weren’t up right now, I would slaughter you!” He roared again and scrabbled away from Rengoku as his grip loosened with the shock he was being exposed to. Tengen crawled away into the darkest shadow he could find and curled up, shivering from the close encounter with the sun. He curled up and clutched at his head, pulling on his two pink, crystal-like horns. “Wait, what?” Rengoku whispered, inching closer to the demon. He hissed at him as he dug his claws into his scalp, blood staining his silky white hair.
A growl emanated from Tengen, growing louder and louder in decibels. Rengoku knew he had to chop his head off, so he decided to raise his sword and forget the words the creature said earlier. As he readied to swing his katana, the sound of a Biwa played, and shoji-like doors appeared on the ground below Tengen. The demon fell through them, and the paper doors vanished as soon as they appeared. A million thoughts ran through the demon slayer’s mind at once. What in the-? Where? When?
It vanished, and the Flame Hashira knew he needed to get back to the scene of the crash. Rengoku decided to forget about it and meet back up with the younger slayers. He sprinted back to where the crash was and found everyone he was looking for. “Look, it’s bug-eyes! I told you he’d be alright, Gompachiro!” Inosuke screamed. Tanjiro looked up from his spot on the ground and saw his mentor running over to them. “Rengoku-san!”, he smiled. The Flame Hashira met up with the rest just as the Kakushi started to arrive. “I’m very proud of all of you! Now, let us get some rest and report on our mission to Oyakata-sama!” Rengoku exclaimed.
What an interesting fight... the slayer thought, his mind going back to the demon. Well, at least everyone is safe...