Jigoro Kuwajima sighed, exasperated by Horitake's impulsiveness. The debt was already taken on—what else could he do? "Fine, Horitake, get in here. You too, kid," he grumbled, opening the door wide.
Inside, Horitake flopped onto the tatami like it was home, kicking off his shoes and dozing by the fire. A week on the road had drained him. Jigoro ignored him, focusing on the trembling Zenitsu Agatsuma. Sitting sternly, he demanded, "Your name?"
Zenitsu dropped into a deep bow. "I'm Zenitsu Agatsuma! Please guide me!"
"Hm. Horitake didn't explain much. Tell me your situation and how you plan to handle your debts."
Zenitsu, desperate after escaping his debt-ridden nightmare, clung to this lifeline. He spilled everything—his debts, his mistakes—holding nothing back, bowing repeatedly to Jigoro.
Jigoro listened, pondering. The debt was hefty but not crippling for him. Something about Zenitsu, despite his cowardice, felt oddly likable. He decided, "Alright, Zenitsu Agatsuma. I'll cover your debts."
Zenitsu's eyes lit up. "Really?!"
"Yes. For now, you'll work as my servant on Peach Mountain. I'll observe you to see if you're worthy of being my disciple."
"Thank you, Grandpa!" Zenitsu kowtowed, overjoyed.
Jigoro nodded, pleased by the "Grandpa" title. By the fire, Horitake peeked at Zenitsu, thinking, Kid, you don't know what being Jigoro's disciple means—hellish training. You won't be this thrilled soon. With that, he drifted to sleep.
Life on Peach Mountain settled into routine. Horitake trained relentlessly, his strength growing. Zenitsu, true to his word, handled chores diligently—cooking, cleaning, chopping wood. Over time, Jigoro grew fond of him and decided to take him as a disciple.
But Zenitsu, having seen Horitake's brutal training, balked. "No way! I can't do that training! I'll die!" he wailed.
Jigoro fumed. People beg to be my disciple, and you refuse? "You're training, like it or not!"
Horitake, grinning mischievously, caught a fleeing Zenitsu, pinned him down, and forced him to bow to Jigoro. Zenitsu's apprenticeship began, kicking off a miserable cycle of training and escape attempts, much like the original story—though unlike Kaigaku, Horitake didn't mock him. He teased Zenitsu with light pranks, never crossing into cruelty.
Over time, bonds formed. Zenitsu saw Jigoro as a strict but caring grandfather, despite the grueling training. He viewed Horitake as a respected, if prankster, big brother. Meanwhile, under Jigoro's guidance, Horitake mastered Total Concentration Constant breathing, boosting his strength further.
Months passed, snow melted, seasons shifted, and Peach Mountain's scenery changed. Then came Horitake's big moment: the Demon Slayer Corps' Final Selection, Taisho Year Two—two years before Tanjiro's batch.
With over a year of training, two system rewards, and Total Concentration Constant, Horitake's physique and Thunder Breathing were near Hashira-level. Passing the Selection would be a breeze. He only wished the system had given another task to push him fully to Hashira strength.
As if on cue, as he prepared for the Selection, the system spoke: "Ding! Zenitsu Agatsuma trusts and respects you as a brother, disrupting fate and triggering a negative butterfly effect: Mitsuri Kanroji's crisis!"
Horitake, fresh from training, hurled his towel down in frustration. "System, explain! How does Zenitsu seeing me as a brother cause this? They're unrelated!"
"In the original story, Kaigaku's mockery meant Zenitsu never truly saw him as a brother, only a senior. Your bond altered fate."
"Seriously? I brought Zenitsu to Peach Mountain, not Jigoro like in the original. That's a bigger change—why no butterfly effect then?"
"You were lucky last time, unlucky now."
Horitake choked. "Fine. But Zenitsu and I are on Peach Mountain, and Mitsuri's who-knows-where. How does this affect her?"
"Butterfly effects involve unpredictable causality."
"Same old excuse," Horitake groaned. "Whatever. What's the task? The reward? What's Mitsuri's situation?"