The newborn's cries had quieted, the storm of emotions finally settling into peace. Without anyone noticing, the moon had slipped away, and in its place, the first light of dawn spread across the sky.
Somewhere in the world, a life had ended. But within the walls of the Rengoku residence, a new life had begun, a fragile bond woven in the night, destined to endure until the very axis of life itself dimmed and vanished.
Shinjuro rose to his feet, letting the first ray of sunlight wash over him. His gaze reflected the blaze of the sun, fierce, unwavering, resolute. Slowly, he turned his head.
Kagerou and Ruka slept soundly, with the newborn Senjuro cradled safely between them, the picture of a family bound by fire and smoke, by blood and choice.
"…You were right, Kage," Shinjuro murmured under his breath. "I'll stop being a Hashira"
The sliding door creaked open. A small, sleepy figure shuffled inside, rubbing his eyes.
"Mother… Kage-nii…" Kyojuro's drowsy voice carried a warmth that seemed to brighten the room.
His half-lidded eyes widened when he spotted Kagerou sleeping beside their mother. But then they went wider still when he noticed something else, something tiny, nestled between them.
"T-That…?"
"That's your little brother, Kyojuro," Shinjuro said gently. "His name is Senjuro"
"…Senjuro?" Kyojuro echoed, padding closer with hesitant steps. The small sound woke Ruka, who smiled softly at her son.
"Mm~ come here, Kyojuro. Come and meet your little brother"
Kyojuro crept closer. Ruka carefully lifted the still-sleeping infant into her arms. Shinjuro leaned in as well, watching as Kyojuro reached out and cautiously poked Senjuro's tiny hand with his finger. Instead of flinching, Senjuro's tiny fingers wrapped around his big brother's.
Kyojuro froze, then broke into a wide, radiant smile.
"Senjuro… big brother will protect you," he declared.
Ruka and Shinjuro exchanged a knowing glance before smiling.
"Huh? Did I say something wrong?" Kyojuro asked, tilting his head.
"No," Shinjuro replied, chuckling. His gaze drifted toward Kagerou, still fast asleep. "It's just… You said the exact same thing as Kage. It made me laugh a little"
"My sons are such wonderful big brothers, hehe~" Ruka added warmly.
"Really?" Kyojuro's eyes sparkled.
"Mm," Shinjuro nodded, and Kyojuro puffed his chest proudly, until his eyes landed on Kagerou again.
"…Why's Kage-nii still sleeping? Isn't he always the first one awake?"
Ruka reached out with her free hand, gently brushing Kagerou's hair.
"Your brother is tired. Let him sleep a little longer"
"Yeah, your Kage-nii is exhausted, both physically and mentally," Shinjuro said softly. Last night was the first time he had ever seen Kagerou, who always acted so mature, cry so freely.
Rising to his feet, Shinjuro looked down at Ruka. "…Kage has done his part. Now, it's my turn to do mine"
"Where are you going, Shinjuro-san?" Ruka asked, her voice carrying both curiosity and worry.
Shinjuro gave her a small smile. "I'm going to speak with Oyakata-sama about something important"
"Shin-"
"Don't worry, Ruka," he interrupted gently, his tone calm but firm. "I thought about this the entire night"
Ruka studied him for a moment, then slowly nodded. "…If you say so"
"Yeah." Shinjuro adjusted his haori and moved toward the door. "Then excuse me. Please tell Kage, when he wakes up… that I'll do as he asked"
With that, he left the room.
---
The journey from the Rengoku estate to Corps Headquarters felt heavier than any battle.
The Demon Slayer Corps Headquarters, a place deliberately kept hidden, shrouded in secrecy.
Nestled deep in the mountains, surrounded by dense forests, its location was never fixed. It shifted constantly, ensuring that even most Demon Slayers could never find it without guidance. Only the Hashira and the Kasugai Crows could reliably reach it.
This secrecy was no luxury, it was survival. If Muzan or the Upper Moons ever discovered the estate, the Corps would be eradicated in a single night.
On one of the winding paths leading to the Ubuyashiki family estate, a lone figure walked steadily. Shinjuro Rengoku.
Kasugai Crows swooped in and out of the estate, delivering messages in hurried beats of wings. Kakushi, dressed in their all-black uniforms, moved quietly about their duties: tending to wounded Slayers, cleaning, escorting visitors, and carrying supplies. Each one who crossed Shinjuro's path paused, bowing respectfully, before resuming their work in silence.
Shinjuro walked with purpose, his footsteps heavy yet resolute. His broad figure cut a stark contrast against the serene estate grounds.
When he reached the gate of the Ubuyashiki residence, the guards stepped aside without question. Shinjuro entered, passing through the quiet corridors until he reached the inner garden.
There, seated formally on the engawa overlooking the garden, was a boy, no older than nine, yet carrying himself with a presence far beyond his years. His pale skin seemed delicate, his body frail, but his eyes… his eyes held a calm wisdom, like still water reflecting the morning sky.
Even as Shinjuro approached, the boy remained composed. A faint, gentle smile curved his lips, as if he had already anticipated the visit.
Shinjuro halted a step away. Then, with a deep breath, he lowered himself to one knee, his posture firm and respectful.
"…Oyakata-sama"
"Shinjuro," Ubuyashiki Kagaya replied softly, his voice fragile yet steady. "It's rare for you to come when there is no Hashira meeting"
Shinjuro bowed his head. "Oyakata-sama… I have something important I must tell you"