The training under Sakonji Urokodaki began immediately. While Tanjiro was subjected to grueling physical conditioning and lessons in Water Breathing, Kanami Reire settled into the role of the house's silent, super-powered caretaker and observer.
Hunting and Absurdity
Kanami used his advanced Speed and Strength to easily hunt boar, deer, and fish, ensuring the house was well-fed. His hunts were so efficient and clean that Urokodaki, still deeply suspicious, could find no fault.
One afternoon, Kanami was observing Tanjiro, who was practicing basic sword swings near a stream. Kanami was perched high on a massive cedar branch, silent and still. His focus was absolute until a small, insect landed directly on his nose.
Kanami, a product of a modern world with a healthy fear of stinging insects, let out a tiny, high-pitched yelp that was instantly muffled. He flinched violently, losing his balance, and tumbled out of the tree with a loud THUD into the ground.
Tanjiro whirled around, clutching his practice sword, only to see Kanami struggling to brush the dust off his robes, his face a mask of embarrassment so He stand straight with cynicism.
"Kanami-san! What happened?" Tanjiro asked, barely containing a burst of laughter.
Kanami scrambled up, smoothing his clothes with dignity. "A... a momentary lapse in concentration, Tanjiro. The environment here is deceptively aggressive. A hazard." He refused to elaborate, quickly retreating to the woods to resume his errands, leaving Tanjiro shaking with silent mirth.
Tanjiro's Inner Resolve
Kanami was often near during Tanjiro's lessons, subtly trying to study Urokodaki's form. He watched as Urokodaki showed Tanjiro the forms of Water Breathing.
(Tanjiro's POV)
The training was hell. Every muscle ached, every breath burned. Yet, the memory of his family's blood and Nezuko's sleeping face kept him going. He watched Kanami-san, who was always returning with food, moving with such effortless grace. Kanami-san was a tragic figure; his story of losing his family to demons and forging his own brutal style felt like a mirror to his own loss, only Kanami-san had chosen a path of raw vengeance.
"Kanami-san had to fight alone for years, and he's stronger than any human I've ever seen," Tanjiro thought, staring at the intimidating, silent figure of the older man with the mask. "He smells of sorrow and power. I need to be that strong. I need the power to protect Nezuko from everything, including Kanami-san's volatile strength, if it ever turns on her. My strength must be pure and protective."
Tanjiro worked relentlessly, eventually learning the ten forms of Water Breathing.
The Uncut Boulder and Sabito's Arrival
A year passed. Tanjiro had mastered the forms, but stood facing the final challenge: a massive, unshakable boulder. Urokodaki told him: "If you can slice that, I will let you go to the Final Selection."
Tanjiro failed for six months. Frustrated and exhausted, he sat defeated.
Suddenly, a boy with a scarred face, Sabito, and a girl with flowered kimono, Makomo, appeared. Tanjiro immediately saw them—not as specters, but as real, alive children. Sabito insulted him, declaring him a failed student. Makomo, the kinder of the two, offered him gentle, vital guidance on his breathing and movement.
Kanami, watching from the periphery of the woods, had another system task
System alert: The protagonist was finally receiving assistance.
Kanami's Test and System Reward
After several more weeks of training with the spectral children, Tanjiro's form changed. His breathing became seamless, his movements flowed like water. He and Sabito fought one final time. Tanjiro won, and as Sabito vanished with a smile, Tanjiro brought his sword down.
CRACK.
The boulder split in two.
Kanami immediately walked out of the woods, a proud smile breaking his serious demeanor.
> SYSTEM (New Mission): Protagonist Validation.
> Goal: Test the Protagonist's current ability. Defeat him in a clean spar and deliver final encouragement.
> Reward: Breathing Technique Comprehension (Skill).
"Your resolve is finally sharp, Tanjiro," Kanami stated, drawing his Nichirin blade. "Let me see how far you've come."
Kanami charged, using his tremendous Speed (16) and a non-lethal, un-devoured version of Form 1: Devouring Gale - First Fang that used raw physical force instead of demon essence.
Tanjiro met him with the Water Wheel. The clash was immediate and forceful, but Tanjiro's perfected technique still couldn't match Kanami's system-granted base stats. Kanami easily bypassed Tanjiro's guard and brought the flat of his blade against Tanjiro's neck.
"It's over," Kanami said, sheathing his sword. "You still lack the sheer muscle power and experience, but your technique, your breathing... it is flawless. You are ready."
> SYSTEM (Mission Complete): Protagonist Validation successful.
> Reward: Skill Breathing Technique Comprehension unlocked.
> Description: Allows the user to rapidly learn and attempt the Breathing Techniques of any Demon Slayer they observe practicing.
Kanami immediately focused the new skill on Tanjiro, recalling his movements.
> SYSTEM (Analysis): Water Breathing (Level 1) acquired.
>
He looked at Urokodaki, who was approaching the shattered boulder.
Kanami felt an immediate, intuitive understanding of the Water Breathing style, from the fundamentals.
The Final Selection and the Spectral Secret
Urokodaki, seeing the boulder split, quietly prepared Tanjiro for the Final Selection.
"Tanjiro," Urokodaki said, his voice unusually strained. There's a chance that you will die, do you still want to go there?
"Yes, I want to get strong, I need to, for Nezuko" Tanjiro replied with determination.
~As Urokodaki gave Tanjiro a new set of clothes and a mask, Tanjiro keeps glancing at Kanami, blushingly.
Hey man, that look on you is kinda scary.. Kanami said. ( Is he a gay now? Did the plot change again? Agh.. This is scary. Will Tanjiro use "Hit me daddy breathing technique?" Kanami thought to his self)
"Uhm.. Tanjiro, perhaps you... Prefer guys?"
"Waaagh! No! No! I was... Can you look out for Nezuko while I'm not here Kanami-san." Tanjiro asked while his face was red because of the misunderstanding.
"Don't worry, you can be assured" Kanami said while puffing his chest and look a little smug.
~Then Tanjiro rushes and waved to Kanami and Urokodaki. "Uhm! Urokodaki-sama, say Hello for me to Sabito and Makamo! I'm going now!
~ Urokodaki gasp as he heard what Tanjiro said. "How did he know those names of the deceased children? Tanjiro-kun..."