My Perfect Isekai: Pragmatic Protagonist, Progression Fantasy and Strategy

The darkness of the cave was thick and choked the lungs. Dave stood barefoot on the freezing basalt, unable to see his own fingers. The moisture hanging in the air settled on his bare chest, leaving a cold layer of water that slowly ran down his tense abdominal muscles. Every breath felt heavy, and the smell of wet clay, old stone, and stagnant air filled his nostrils. The movement of the air was the only warning he could expect in this absolute void of physical senses. Dave did not move, letting his feet adapt to the rough texture of the rock. Every muscle in his body was tense, ready for an immediate reaction, though his eyes remained useless in this subterranean tomb.

Crack!

The Sensei’s bamboo cane struck right past his guard and hit his left rib. The force of the blow slammed the boy into the stone wall, and a low rattle escaped his throat. Dave slid down onto the stone rubble, tasting the rusty flavor of blood on his tongue. The strike was clean, fast, and saturated with hostile KAI, which hit his nerve plexus with the force of a battering ram. Pain exploded in his chest, but Dave did not allow himself the luxury of panic. Instead, he activated his practiced system of controlled masochism. For him, pain was only a raw input signal, a clean dataset containing the force of the strike, the angle of attack, and the opponent’s position in the dark. He stretched his massive shoulders until his bones popped with a loud crack. He slowly raised his hand and wiped the blood onto his cheek, without uttering a single groan.

”Too slow, kid,” the old man’s gruff voice came from the void, revealing no direction. ”You are still trying to look with your ears. Your head is analyzing the noise instead of becoming part of this cave.”

Dave stood up without haste, drawing his heels to the slippery ground. An insolent grin crept onto his bloodied face.

”Just warming up, Sensei.”

Dave did not use mana. His pathways were not blocked by any external barrier—he simply ignored Software 1 with complete premeditation. Using sapphire slime, lightning, or any magic was pointless. This was a rigorous training of Yomi KAI, not a spellcasting lesson. The boy had to rely solely on his raw Vessel and the deepest depths of his own soul. On pure KAI, which was his own strength. A ruthless expression of will, completely independent of magic and astral pathways, which no one in the universe could strip from him. Every breath of the old man, every drop of water falling from the cave ceiling was analyzed by his mind.

His hyperactive mind went wild in the darkness. ADHD caused him to register every tiny rustle, falling stone, the friction of the old man’s clothes, and the humidity of the air. Trying to force a statue-like peace was a mistake he had made during the first days of training. Traditional meditation and trying to quiet his thoughts only blocked the flow of energy, making his body rigid and vulnerable to blows. Pure logic pointed to a completely different solution. Why should he fight his own nature when he could turn this mental storm into a precise tool for mapping reality? If his brain processed thousands of stimuli per second, he had to give it the proper fuel.

Instead of passively listening to the environment, Dave focused his will. He sent out silent, spherical pulses of pure KAI from his soul. Waves of energy spread through the chamber, bypassing the physical limitations of sight. The pulses bounced off the uneven basalt, wet formations, sharp stalactites, and the moving silhouette of the Sensei, returning directly to his spiritual reactor as a precise echo.

This was the birth of Yomi Stage II. An active KAI sonar.

In a fraction of a second, Dave’s perspective jumped out of his body. A three-dimensional model of the cave was born in his head. He saw the chamber, himself, and the Sensei from a third-person camera. The image was not static—it was dynamic, refreshed with every subsequent wave of KAI radiating from his chest. He saw the alignment of the old man’s feet, the cracks on his bamboo cane, and the smallest crevices of the stone ceiling. It was a complete visualization of the space, free from the limitations of biological sight.

Suddenly the air shifted. The Sensei launched a fast, lethal slash with the cane, aiming directly at his right temple. The movement was incredibly fluid, devoid of any unnecessary preparation that could betray the intention of the strike.

Dave did not dodge. Because his attention had left his physical body, the Vessel became vulnerable by default. However, his will reacted with a machine-like reflex forged during hundreds of dungeon encounters. In a fraction of a millisecond, he concentrated the raw drive of his soul precisely at the point of the inevitable impact.

He triggered passive Gōtai.

The bamboo cane struck the invisible coating around Dave’s arm and bounced off with a loud, metallic screech, as if it had hit solid steel instead of human flesh. The force of the recoil jarred the old man’s wrist. The old man hissed in pain, losing his balance for a moment and taking a step back. The wood of the cane cracked slightly at the very tip, unable to pierce the barrier made of pure will. Dave felt the energy of the blow spread through his arm, but the passive shield absorbed the entire momentum, preventing any muscle damage.

”First calibration completed successfully,” Dave muttered, brushing an invisible speck of dust from his shoulder, though the pain from the earlier blows still pulsed beneath his skin, reminding him of the price of every mistake.

”Your attention is not calm water, boy. It is a bloody storm,” the old man retreated deeper into the cave, and a moment later a small campfire flared in a distant corner, scattering the dark with a red glow. ”But instead of choking it, you arranged the storm into a radar. That is a smart optimization. Many warriors try to clear their mind, searching for a void they will never reach because their nature is different. You accepted your internal chaos and made it a precise tool.”

Dave walked over to the fire and sat on a hard stone, taking a clay cup of steaming, dark brew that the old man had prepared earlier. The warmth of the liquid slowly spread through his tired body, bringing relief to his aching muscles and helping with faster recovery.

”Pure logic, Sensei. Why should I fight my own nature? My brain works faster, registers more stimuli. Trying to silence that was a useless waste of energy. The KAI sonar allows me to process all this information without overloading my biological senses. I see everything without looking at anything.”

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”True style is not born from copying ancient books,” the old man muttered, releasing a slow trail of grey smoke from his old, wooden pipe. ”It is born from who you are. But remember, the hard armor of will will break if your KAI flow encounters the slightest resistance. You must learn absolute fluidity. Gōtai cannot be a rigid shield that you put up like a wall before an impact. It must be like a river that freezes in a fraction of a second under the frost, and then immediately returns to a liquid state so as not to restrict your movements. If you freeze the flow of energy for too long, you will lose mobility.”

Dave listened to the old man’s words in complete silence, maintaining a light, insolent smile on his face. He did not interrupt him, as he was curious if the old master had mixed up the basic theories of spiritual energy and tried to simplify something in a stupid way. Dave knew the theory of KAI perfectly, but he wanted to verify the teacher’s craft. It turned out that the old fighter had hit the nail on the head. Dave quickly translated the poetic comparison of the freezing river into his own precise language. It was pure flow physics, what he classified in his head as interval phase switching—a technique of activating the hardness of Gōtai only in the fraction of a second of the impact itself, to maintain one hundred percent flexibility and speed during the rest of the time.

”Didn’t mess anything up,” Dave thought with satisfaction, taking a slow sip of the bitter brew. ”The old man knows his stuff. A rarity in this world full of mystical nonsense and gods.”

Dave nodded briefly, letting his Vessel slowly regenerate by the heat of the campfire. His thoughts drifted for a moment toward the manor house under Crossgard. A significant amount of time had passed since he left his Crew to undergo this rigorous training in the caves of Yomi II. Thanks to the blue communication thread and Kaede’s radar, which had been transferred to Shnee as a familiar pact, he knew that the girls were not idle. Shnee and Karys were currently slaughtering the deep floors of the wild dungeon, obtaining valuable resources, rare cores, and clearing the area around their base.

He knew that Karys had already received her light armor from Berthold the armorer. This leather armor was designed to perfectly protect the base of her spine and her black tail, without restricting her dynamic movements in battle. Elena held the entire logistics of their enterprise with an iron hand, managing finances, purchases, and supplies, while Mina took care of high-calorie meals and her legendary ramen, which allowed the girls to recover rapidly after hard expeditions. Even little Ria was learning the craft, showing huge potential. Everything worked like a perfectly oiled combat machine. This was not a regular manor—it was a predatory syndicate that was slowly taking control of the local market and dungeon resources.

”I must forge myself into a monster so that I am not the only weak link in this predatory syndicate,” Dave thought, tightening his grip on the clay cup until the clay cracked slightly under the force of his fingers. ”When I return to the manor, my KAI must be at a level that allows me to crush any opponent without relying on mana. Magic is a tool of the gods, and the gods can take it away at any moment. KAI is my own soul. My rules.”

The boy set the cup down on a flat stone and stood up, returning to the basalt plate that served as his training arena. He tucked his hands behind the belt of his boxing shorts, imitating his constant, insolent habit of keeping his hands in the pockets of his leather coat. He closed his eyes, letting the darkness once again take control of his physical senses. He stood stable, feeling every unevenness of the rock under his bare feet. His breath was calm, steady, perfectly synchronized with his heartbeat.

”Once more, Sensei. This time without any mercy. Show me your full speed.”

The old man smiled slightly, revealing a toothless mouth, set his pipe aside, and raised the bamboo cane. He charged with an inhuman speed. The wood turned into a thick net of deadly lines, whistling through the air and cutting the dark with terrifying force. Every strike was launched with lethal accuracy, aimed at the vulnerable points of his body—knees, ankles, solar plexus, and throat. The attacks came from all directions, forcing the boy into continuous, flawless analysis of the surroundings.

Dave combined the active sonar of Yomi II with the Lynx Footwork for the first time.

The cane whistled right past his ear, brushed the tight skin on his neck, and flew over his head, but Dave did not even blink. His body moved in the broken rhythm of the Lynx Footwork, completely breaking the old man’s prediction. A quick spin, a minimalist step to the side, raising his arm at a perfect angle to slide the strike off his passive Gōtai, and another jump to a safe distance. Dave did not try to counterattack—his sole goal was defense and the perfect calibration of his senses. Every movement of his was economical, angular, devoid of any unnecessary embellishments that could throw him off balance.

Instead of traditional, wide dodges, the boy reacted to the smallest air shifts registered by the radar. He moved low, performing minimalist, angular dodges millimeters away from the speeding wood. With every sudden jump, tiny sparks of sapphire plasma shot from his bare feet with a loud crack, burning blue prints into the black basalt. The smell of ozone and burnt stone began to rise in the cave, mixing with the humidity.

Dave flowed around the Sensei’s attacks, estimating the path of the strikes on the fly, which saved his brain’s valuable energy. He maintained an absolute, insolent ease, which drove the old man to fury, yet simultaneously filled his heart with pride. The boy did not fight the cave or the darkness—he became part of them, using every detail of the environment to his advantage.

The sparring ended in sudden silence. The old man lowered the cane, breathing heavily, and a deep respect shone in his blind eyes.

”You did it, kid...” the Sensei wheezed, leaning on the cane like an ordinary walking stick. His chest rose heavily, and sweat dripped down his wrinkled face. ”You mastered the second stage of Yomi in a time that would take others years. Your calibration is terrifying.”

Suddenly the ground beneath their feet shook with a low, disturbing bass. The vibration was deep, slow, and carried a massive charge of pure energy, causing the small stones at the bottom of the cave to jump with a quiet rattle.

Dave froze. His newly calibrated Yomi II radar suddenly went wild. The three-dimensional image in his head began to flicker, break, and fall into chaotic pieces, and his analytical mind suffered a massive shock. The active KAI scan registered an energy signature that did not fit any known template of monsters or magic of this world. This was not mana, this was not KAI, this was not even the natural life energy of this continent.

This was an unnatural, metallic energy vibrating with cold ether.

Exactly the same strange, dark vibration that Dave had sensed on the melted metal in the Forgotten Necropolis, when he first collided with technology that should not exist in this world. The smell of ozone and burnt copper hit his nostrils, paralyzing his senses for a moment.

The active sonar, which had been vibrating until now, died in a fraction of a second, replaced by a massive spike of anomalous power that froze the air in the chamber. The moisture on the cave walls instantly turned into frost, and Dave’s breath escaped his mouth as a thick, white cloud.

From the deep crack, right beneath their feet, a slow, metallic screech of gears resounded, as if a giant mechanism hidden beneath the basalt plates had just been forced to move after thousands of years of inactivity. An insolent smile slowly returned to Dave’s bloodied face. He clenched his fists, feeling pure adrenaline begin to course through his veins.

”And now the real fun begins,” he muttered quietly, staring into the widening crack from which icy, dead air billowed.