Reborn in Diamond no Ace

Years passed, and Renji Arata was now in middle school. He stood in front of the mirror one morning, inspecting his reflection. At 13 years old, he was growing steadily, his once-small frame now lean and athletic. His black hair fell slightly over his forehead, and his dark eyes reflected a quiet determination.

Renji flexed his arms experimentally, noting the tone but lack of bulk in his muscles. His physique wasn't imposing; it was built for speed, precision, and endurance rather than raw power.

"Not bad," he thought, running a hand through his hair. "It's not like I need huge muscles for baseball anyway. I just need to stay agile and keep my shoulder strong."

He had worked tirelessly over the years, sticking to his rigorous physical exercise routine. Mornings were for running, evenings for calisthenics and light weight training. His focus was unwavering, his goal clear: to build a body that could endure the demands of a professional baseball career.

Yet, a part of him couldn't ignore the subtle tension at home. His parents had always supported him, but their disappointment that he hadn't joined the school's baseball club was palpable. They never voiced it outright or pressured him, but he could see it in their eyes whenever they watched him train. Their son—a natural talent with a passion for the game—had chosen not to compete.

"I'll show them one day," Renji thought, determination flaring in his chest. "When I'm ready, they'll understand."

After school, Renji headed to his favorite spot: the neighborhood batting cage. It was a small, unassuming establishment run by an elderly man named Masaru-san. Despite his age, Masaru-san still had a sharp eye for talent and was well-known in the area for nurturing young players.

"Renji-kun, you're here again," Masaru-san greeted him with a warm smile as Renji entered the cage.

"Of course," Renji replied, returning the smile. "Can't stay away." He slipped on a pair of worn batting gloves, stepped into the cage, and picked up a bat.

The pitching machine's gears whined, a mechanical growl that filled the netted cage. A blur of white flashed from the machine's arm, and Renji's muscles tensed. He'd been practicing for hours, but each pitch still demanded his full focus.

Crack! The bat connected with the ball, a sharp, clean sound that vibrated through Renji's hands. The ball rocketed towards the back of the net, a white streak against the green mesh. The machine fired again, a tighter, faster pitch this time. Renji adjusted his stance, his eyes glued to the ball. He could almost feel the air pressure change as it spun towards him.

He swung, a powerful, fluid motion. Thwack! This hit was different, a deeper, more resonant sound. The ball soared, a line drive that seemed to defy gravity. Sweat stung Renji's eyes, and his grip on the bat tightened. He was lost in the rhythm of the machine, the constant barrage of pitches pushing him to his limits.

Another pitch, a low curve that dipped at the last second. Renji reacted instinctively, dropping his hands and snapping the bat through the zone. Crunch! He'd caught it on the end of the bat, a less than perfect hit, but still solid. The ball flew off to the side, a testament to his quick reflexes.

Masaru-san watched from the bench, his eyes narrowed in concentration. "You're seeing the ball well, Renji," he said, his voice cutting through the mechanical hum. "But you're still holding back. Let that power flow!"

Renji paused, catching his breath. He could feel the burn in his forearms, the slight tremble in his legs. He looked at the machine, its relentless rhythm a challenge. He gripped the bat tighter, his knuckles white.

The next pitch was a fastball, straight down the middle. Renji unleashed everything, a full, explosive swing. BOOM! The ball exploded off the bat, a thunderous crack that echoed through the cage. It was a towering fly ball, a perfect hit that would have sailed far beyond any outfield.

Renji watched it disappear into the netting, his heart pounding. He could feel the power surging through him, a raw, untamed energy.

Masaru-san nodded, a flicker of something close to awe in his eyes. "That's it, Renji," he said, his voice low. "That's the power I was talking about. You have a gift. Don't waste it, boy."

Renji's smile faltered for a moment. He knew Masaru-san was right, but he wasn't ready to fully step onto the stage just yet. He still had work to do.

After finishing his batting practice, Renji moved to the pitching area. He stepped onto the mound, gripping the baseball firmly in his hand. The familiar weight of it grounded him, focusing his thoughts.

Taking a deep breath, he positioned himself, his lean frame coiled like a spring. His arm snapped forward, the ball slicing through the air with pinpoint accuracy. It slammed into the target's center with a satisfying thud.

"Still got it," Renji muttered, a small smile tugging at his lips.

He continued, throwing fastball after fastball. Each one hit its mark, the rhythm of his pitches almost hypnotic. His control was remarkable, each throw an extension of his will. He varied the speed, sometimes unleashing his full power, other times pulling back just enough to test his precision. The sound of the ball hitting the target resonated like music to his ears.

Masaru-san watched silently, his expression unreadable. When Renji finally stepped off the mound, his arm tingling with exertion, the old man approached him.

"You've got control and speed, Renji. But remember, pitching isn't just about hitting the target. It's about outsmarting the batter. Keep that in mind."

Renji nodded, absorbing the advice. "Thanks, Masaru-san. I'll keep working on it."

As he packed up his gear and headed home, the evening air cool against his skin, Renji felt a deep sense of satisfaction. His path was far from easy, but every swing, every throw, every bead of sweat was bringing him closer to his goal.