Reincarnated As Young King of Meteor City(Meruem-HxH)

The next day, the training hall was steeped in a focused silence, the air pulsating with the controlled energy of the newly-awakened Nen users. The four young warriors sat cross-legged, eyes closed, their Nen flowing around them like ethereal auras. They had managed to keep their energy from wildly seeping out, a testament to their relentless training and sheer determination.

Koshiro, standing at the room's center, nodded approvingly. His voice broke the silence, resonating with decades of wisdom and authority. "Good. You've managed to contain your Nen. Now, the real training begins."

All eyes were on him as he began to discuss the fundamentals of Nen, the mystical life energy that resided within them. "Nen is divided into four basic abilities: Ten, Zetsu, Ren, and Hatsu. You've been unknowingly practicing Ten, which involves creating a shroud around your body to prevent your Nen from leaking out."

"Next is Zetsu," he continued, his gaze intense. "It involves shutting off your own aura completely. Doing so makes you invisible to other Nen users and allows you to recharge your own Nen. But be warned, using Zetsu leaves you vulnerable to physical and Nen attacks."

As he talked, Haruto's expression was intense, his eyes reflecting an insatiable hunger for knowledge. His mind was a sponge, soaking up every word Koshiro spoke, analyzing, and storing them for future use. His inherent kingly traits, his natural command and charisma, were now being bolstered by knowledge and wisdom.

Koshiro moved onto Ren, "This technique involves increasing your Nen flow. It enhances your physical strength and durability and is key to powerful Nen attacks. But remember, higher Nen flow means faster exhaustion. You need to learn to balance it."

Feitan's eyes glowed at the mention of enhanced physical strength, a wicked grin spreading across his face. The idea of possessing such power excited him. His ruthless nature was drawn to anything that promised greater strength and dominance. Haruto noticed this and smirked, amused by Feitan's predictability.

Finally, Koshiro introduced Hatsu, "Hatsu is the culmination of your Nen practice. It's your personal expression of Nen, unique to you and you alone. Your Hatsu will reflect your personality, your desires, and your goals."

"Remember, the journey towards mastery in Nen is not a sprint, but a marathon," Koshiro said, leaning against a wooden pole, his gaze scrutinizing his young pupils. "Hatsu may seem exciting, but it is the highest pinnacle of Nen control. You will reach it in due course. For now, let us focus on mastering Ten, Zetsu, and Ren."

His words, steeped in wisdom, resonated in the silent training hall. Haruto, the youngest of the four, with his body still thrumming with the energy of his freshly-awakened Nen, nodded. His eyes were sharp, mirroring Koshiro's intense gaze.

"Let's start with Zetsu," Koshiro commanded, folding his arms over his chest. "Shut off your Nen completely. Make it seem as though you've vanished."

Surprisingly, as the young ones concentrated on concealing their Nen, the energy swirling around them receded. The vibrant aura that once surrounded them disappeared, replaced by an eerie silence. Koshiro observed, a hint of surprise creasing his weathered face.

"Good," he mumbled, "the skills you've honed as assassins have paid off."

Phinks, ever the talkative one, chuckled. "Hiding is our second nature. Seems our previous training wasn't entirely useless, eh?"

Feitan shot him a glare, before turning to Koshiro. "We've done it. What's next?"

"Ren," the old man said, pointing to the space in front of him. "Aim to increase your Nen flow. Envision your energy amplifying."

As they grappled with this new task, their Nen flickered back to life, wild and untamed. They struggled to control the surge, their bodies trembling under the onslaught of their own power. But despite the struggle, there was a stubbornness in their eyes. They wouldn't back down.

"Ren...this is the essence of our strength, isn't it?" Feitan muttered, his words dripping with newfound understanding. His eyes were sharp, a wicked grin pulling at his lips as he felt the surge of energy within him. He was a fighter through and through, and the promise of amplified strength excited him.

Meanwhile, Haruto was silent, deep in concentration. His energy was stirring, responding to his demand. As his Nen grew stronger, it didn't become a chaotic tempest like before but remained a controlled inferno. His command over his Nen was growing, much like his latent kingly aura.

"Control it!" Koshiro barked, snapping them out of their internal struggle. "Remember, this is a part of you. Do not let it overpower you. Command it."

"I'm trying!" Phinks grumbled, beads of sweat trickling down his face. The strain was evident on his face, but there was a gleam of determination in his eyes. He wouldn't back down, not yet.

Amidst their struggles, Canary was remarkably silent. She sat cross-legged, her face pinched with concentration. Her energy whirled around her, tumultuous and stormy, but she held her ground. Her focus was unwavering.

Days rolled into weeks, with their time in the training hall dedicated to mastering Ren. Every morning, as the sun's first rays bathed the room, Koshiro would command them to activate Ren and increase their Nen flow. The goal was simple - sustain the surge longer each time.

Haruto, with his royal lineage, was the first to grasp the essence of Ren. His gaze held an unyielding resolve as he focused his energy, refusing to let it overpower him. He would sit in silent determination, his Nen dancing around him like a controlled firestorm.

Feitan, with his inherent fierceness, took to the practice like a moth to a flame. The idea of strength and power fascinated him. "This," he had declared one day, a hint of a cruel grin playing on his lips, "is what I'm made for." His Nen was like a fierce beast, growling and snapping, but under his command.