Demon Slayer: Echoes of Resolve

The following months became a blur of relentless training for Kaito, each day more grueling than the last. Jigoro Kuwajima wasted no time in throwing him into the deep end. The old man's methods were anything but forgiving, and his sharp tongue and critical eye left no room for complacency. Yet, despite the seemingly impossible challenges, Kaito pressed on, his resolve as unwavering as ever.

--

One of the first tasks Jigoro assigned to Kaito was carrying heavy boulders up and down the slopes of Mount Hakobe. Kaito stared in disbelief at the enormous, uneven rock Jigoro pointed to, its surface slick with moss. "You want me to carry that? Up there?" Kaito asked, glancing at the steep trail leading higher into the mountain.

Jigoro leaned on his cane, his amber eyes cold and unyielding. "No Demon Slayer worth their salt ever got strong without building their endurance first. This is what separates the weak from the strong. If you can't carry that rock, you won't last a second in a real fight."

Kaito gritted his teeth and bent down to wrap his arms around the boulder. It was heavier than he'd anticipated, and his muscles screamed in protest as he heaved it off the ground. The incline of the trail made every step agonizing, and his feet slipped on the loose gravel more than once. Kaigaku, ever the cynic, leaned casually against a nearby tree, watching the ordeal with a smirk.

"You look like you're about to keel over," Kaigaku called, his voice dripping with mockery. "You sure you've got what it takes?"

Kaito ignored him, focusing instead on the rhythmic pounding of his heart and the sharp burn in his arms. Every step was a battle, but he refused to stop. By the time he reached the designated marker and lowered the rock to the ground, his body felt like it was about to collapse. Despite the pain, he stood tall and met Jigoro's gaze.

The old man nodded curtly. "Good. Again."

And so it went, day after day. Kaito's muscles ached constantly, but he noticed that he could carry the boulder a little further each time. His balance improved on the rocky terrain, and his body gradually grew stronger. The once-impossible task became a grueling but manageable routine, and Kaito took pride in the progress he was making.

--

"Breathing is the foundation of everything," Jigoro said one morning, his voice sharp as the chill air. "It's the key to strength, speed, and focus. Without mastering Total Concentration Breathing, you're just a man with a sword."

Kaito nodded, sitting cross-legged in the clearing as Jigoro explained the technique. The older man demonstrated by taking deep, controlled breaths, his chest expanding and contracting with precision. "Feel the air fill your lungs," Jigoro instructed. "Let it flow through your entire body. This isn't just breathing—it's a method of survival. It's what keeps us alive in the face of death."

Kaito closed his eyes and focused on his breathing. At first, it felt unnatural, and his concentration wavered. The rhythm was difficult to maintain, and his mind constantly wandered. Jigoro's sharp rebukes were quick to follow.

"Focus!" the old man barked. "A scattered mind will get you killed."

Kaigaku, of course, found endless amusement in Kaito's struggles. "Wow, you can't even breathe properly? No wonder you're behind," he sneered.

But as the days passed, Kaito's control improved. He began to feel the difference in his body—his movements became more fluid, and his stamina increased. He found that even in the midst of carrying boulders or running up steep trails, the controlled breathing allowed him to push past his limits. It was a small victory, but it bolstered his determination.

--

One crisp morning, Jigoro gathered both Kaito and Kaigaku in the clearing. The tension between the two young men was palpable, but Jigoro ignored it. Instead, he unsheathed his katana and stepped into a stance Kaito hadn't seen before.

"Today, I'll teach you the basics of Thunder Breathing," Jigoro announced, his voice carrying authority. "Kaigaku, you've already been practicing for months, but you can always improve. Kaito, this will be new for you, so pay close attention."

Kaito's heart raced with a mix of excitement and nervousness. He'd heard Kaigaku boast endlessly about Thunder Breathing, describing it as one of the fastest and most powerful styles. Now, he would get to learn it himself.

"This is the First Form: Thunderclap and Flash," Jigoro explained. "It's the foundation of Thunder Breathing. Speed is everything—faster than your opponent can react, faster than they can even think."

Before Kaito could fully process the words, Jigoro moved. The world seemed to blur for an instant, and then he was on the other side of the clearing with a trail of lightning following him, his blade glinting in the sunlight. The sheer speed of the technique left Kaito awestruck.

"Whoa," he whispered, his neon-green eyes wide with awe.

Kaigaku, standing beside him, smirked. "Impressive, huh? Don't get any ideas, though. You'll never be able to pull it off like I can."

Kaito ignored the taunt and focused on Jigoro, who had returned to his original position. The old man sheathed his katana and turned to Kaito. "Thunder Breathing requires precision and discipline," Jigoro said. "It's not just about moving fast—it's about breathing in harmony with your body, channeling your energy into every step and strike."

Kaito nodded, determined to learn. Jigoro handed him a practice sword and gestured for him to step forward. "Start with the stance," he instructed. "Feet apart, knees slightly bent. Your weight should be balanced, ready to spring forward at a moment's notice."

Kaito mimicked the stance, feeling awkward and unsteady. Jigoro adjusted his posture, nudging his shoulders into place and correcting his footing. "Good," the old man said. "Now, focus on your breathing. Inhale deeply—feel the energy build in your core. When you move, let that energy explode outward like lightning."

Kaito took a deep breath, feeling the air fill his lungs. He tried to channel the energy as Jigoro had described, but his first attempt was clumsy and slow. He stumbled as he lunged forward, nearly tripping over his own feet.

Kaigaku's laughter echoed through the clearing. "Pathetic," he sneered. "You're never going to get it at this rate."

"Kaigaku," Jigoro said sharply. "Enough."

Kaito gritted his teeth and tried again. Each attempt was marginally better than the last, but it was clear he had a long way to go. His movements lacked the fluidity and speed that Jigoro and even Kaigaku possessed. Still, he refused to give up.

Over the next few weeks, Kaito devoted himself entirely to mastering the basics of Thunder Breathing. He practiced Thunderclap and Flash until his legs felt like they were on fire, his muscles screaming in protest. Jigoro's critiques were harsh but fair, and Kaito absorbed every piece of advice like a sponge.

Kaigaku, meanwhile, continued to flaunt his superiority at every opportunity. His movements were swift and precise, and he took every chance to remind Kaito of how far behind he was. But instead of letting Kaigaku's taunts discourage him, Kaito used them as motivation.

Slowly but surely, Kaito's efforts began to pay off. His breathing became more controlled, his movements more fluid. Though he wasn't as fast as Kaigaku, he could feel himself improving with each passing day. By the end of the third week, he managed to execute a rudimentary version of Thunderclap and Flash, his body surging forward in a burst of speed.

Jigoro watched him closely, nodding in approval. "You've got potential," he said. "But potential means nothing without effort. Keep at it."

Kaito wiped the sweat from his brow, his neon-green eyes blazing with determination. "I will."