Late July, 2092
In a quiet residential area far from Tokyo's bustling core, a grand dojo sat atop a modest hill. This region, reshaped by post-war redevelopment and shelter installations from the Global Outbreak War, housed the Tokyo Branch of the Shinei-ryu Sword and Martial Arts Dojo. Open to all, regardless of magical aptitude, its disciples excelled in police, military, and firefighting roles. Combining swordsmanship, hand-to-hand combat, and complementary magical skills, Shinei-ryu was a comprehensive martial art, indispensable to Japan's security forces, political elite, and even non-mages seeking mastery.
"Hah! Tcha!"
Five years had passed. No claiming it was "just a dream" now. Yuto Mitsuya sparred against a group of advanced disciples, wielding no magic yet toppling them one by one. Even those with wooden swords were disarmed and thrown effortlessly.
Watching with satisfaction was a burly man in his forties, built like a pro wrestler. Beside him, a young woman sat in seiza, observing with a sigh.
"Hah! At this rate, we'll have to grant Yuto the title of assistant instructor!" boomed Gozo Kamiizumi, Yuto's maternal grandfather and Shinei-ryu's headmaster. A doting grandparent, he was indulgent to a fault.
The sighing woman was Shizuru Mitsuya, Yuto's eldest sister and a prodigy who'd already earned assistant instructor status despite her youth. "Grandfather, he's only twelve. Awarding it after just five years would tarnish Shinei-ryu's name. The predecessors would weep."
Gozo's praise might seem excessive for Yuto's age, but Shinei-ryu never favored kin. Sloppy technique harmed both self and opponent, a truth Gozo knew well. This sparring session doubled as a test, with advanced disciples some near assistant instructor level mixed in. Yet Yuto floored them all.
Shizuru's concern wasn't mere formality; she worried about the strain on her growing brother. Overtraining could stunt his development. Gozo, recognizing Yuto's prodigious talent from their first meeting, trained him like a prized disciple, pushing regimens that could injure even advanced students. Shizuru often scolded him for it, but Yuto's resilience inspired her own efforts. Still, she hoped to spare him stunted growth.
Sensing her intent, Gozo spoke. "I understand. This sparring is to gauge him. More strain could harm his growth. Say a word, and he'll ease up. Though, you and Mototsugu aren't ones to talk about overdoing it."
Shizuru flushed. "…My apologies."
Yuto's recovery from his mysterious fever had rippled through the family. Shina studied harder, Mototsugu and Shizuru honed their skills, and even Kana and Mika began dojo training. Motoharu, the eldest, took up self-defense, inspired by Yuto. When Gozo asked Gen if he'd forced them, Gen replied, "I suggested it to Yuto, but he begged to train. His drive spurred the others."
Gen apologized, but Gozo roared with laughter. Yuto's influence had even motivated the heir apparent, proving his value to the Mitsuya.
"The Nine Schools Competition is next month, yes? No overexertion," Gozo warned Shizuru. "As a Mitsuya, you can skip dojo training for it."
The Nine Schools Competition showcased their progress. Mototsugu, now graduated, and Shizuru, a third-year, had excelled, securing First High's victories and elevating the Mitsuya name. Kana (second-year) and Mika (first-year) were also selected, their trio drawing attention. With First High aiming for an unprecedented third consecutive win, tension was high. Gozo's rare mention of "Mitsuya" startled Shizuru.
A buzz-cut youth approached. Gozo sighed, muttering, "Late."
"Gramps, you're freaking Shizuru out. And you, Madam President, don't overdo it," said Mototsugu Mitsuya, Yuto's second brother and an assistant instructor. A magic university student, he was betrothed to his childhood friend and cousin.
"Finally here, Mototsugu. Babysitting the Yaguruma kid?" Gozo teased.
"Saburo's got potential. Yuto's dragged him through enough to prove it. His dad's worried about where he's headed, but with Shina in mind, his growth isn't bad."
Saburo Yaguruma, from a family serving the Mitsuya for thirty years as guards and staff, was two days apart from Shina. Yuto had targeted him for "training" disguised as magical experiments. Mototsugu, coaching him in Shinei-ryu, saw Yuto's foresight when he explained, "If Shina stays dependent on me, she'll never find a suitor. So I'm… forging Saburo." Mototsugu, wary of Yuto's experiments, ignored the "test subject" part but agreed Shina's brother complex needed addressing.
"You're high on him, eh? Fine, I'll train him myself!" Gozo declared.
"Stop, Gramps! Yuto went easy on him. You'd crush him. Retire already, you ageless geezer," Mototsugu shot back.
"Retire? I'm a lifelong warrior!" Gozo roared.
The Kamiizumi weren't a numbered mage clan, unlike the Mitsuya. Descended from the legendary swordsman Nobutsuna Kamiizumi, they'd integrated mage bloodlines, evolving Shinei-ryu into a blend of swordsmanship, martial arts, and magic. Once called Shinkage-ryu, it became Shinei-ryu Sword and Martial Arts. A branch, the Chiba Clan's Senba-ryu, influenced military and police, but revered Shinei-ryu as its origin. The Kamiizumi also trained the Twenty-Eight Families and owned the Third Magic Research Institute, sponsoring the Mitsuya.
Gozo's connections were legendary. A comrade of the revered Retsu Kudo, he'd fought alongside the late Genzo Yotsuba, avenging wrongs against Konronhouin and Dahan. Respected as a "master" by current clan heads, he shunned leveraging his status, knowing the perils of misused power.
Yet, Shiho's marriage to Gen was no political arrangement just childhood sweethearts in love. The assumption of a strategic match only amplified Gozo's fearsome reputation, to his wry amusement.
"Retire? Go meet your old pals in hell!" Mototsugu jabbed.
"If Yama blocks my path, I'll cut him down!" Gozo retorted.
Their sparring erupted, a clash of Shinei-ryu secret techniques in close combat, too lethal without them. Disciples, including those Yuto defeated, watched raptly, halting the session. Yuto approached Shizuru.
"Good work, Yuto," she said.
"Thanks, Shizuru-neesan. But… what about that?" He pointed at Gozo and Mototsugu's duel.
Shizuru sighed. "It'll last thirty minutes at least. Yuto, fetch Senri. She's probably prepping in the kitchen."
"Got it. Best solution." Yuto hurried off.
Senri, Gozo's granddaughter and Mototsugu's fiancée, was perfect for stopping them. She arrived, and both were sentenced to an hour of waterfall meditation as punishment.
Five Years Later
I've grown stronger physically, at least. "Stronger" feels like an understatement, but saying it aloud feels like tempting fate.
Thanks to Dad's arms brokering, I easily acquired CADs, accelerating my designs. I sold blueprints for commercial CADs to FLT via Dad, earning a hefty sum and his good mood.
I also invested in Saburo Yaguruma. In the original story, his weak magic aptitude got him sidelined as a guard. My solution? Boost him. Knowing his Magic Calculation Area was partially occupied by movement-type magic, I made him a test subject for a spell I'd refined over five years, perfected after my initial inspiration.
Non-Systematic, Mental Structure Interference Magic: [Reinforce]
Primarily for treating Magic Calculation Area overheating, it also compresses and strengthens the area in the subconscious, repairs physical limiters, enhances bodily strength, and fortifies psion information bodies. I developed it to prevent my own overheating during auto-repair spells and to aid mages with occupied calculation areas. Testing my own limits? Too risky—self-destruct attacks are off the table.
Saburo's experiment succeeded. He gained above-average calculation capacity while retaining his innate magic. Done while he slept, no one knows. I also used him to test [Kaleidoscope]'s range—not to bully him, but to benefit us both. Shina's complex makes things awkward, though. She's my sister, not a romantic option, and Saburo should get that, but his glares persist.
While tinkering with a new device in my room, a knock came. It was Motoharu, the eldest.
Months after my fever, I'd confessed my reincarnation to Dad, begging him to let Motoharu inherit the clan. Even with my cheat-like abilities, my skills were untested then, and family disputes seemed exhausting. The next day, Motoharu visited, probing. I dodged the reincarnation bit, saying, "As the third son, I'll leave the family anyway."
Now assisting Dad's arms business, Motoharu's preparing to lead. He instantly recognized my project. "A long-range CAD? No, a rifle-type booster for extended range."
"Spot on. Personalized CADs are better, but… sorry, Motoharu-niisan," I said.
"No need to apologize. I came with business. Finish up," he replied.
Pausing, I faced him. "What's up?"
"Dad's sending me to Okinawa. Rough timing, huh?"
"Mid-summer heat? Why?"
"Not tourism, sadly. Remember Lieutenant Sanada? The army guy who visited, fascinated by you?"
"Yeah. His stare was intense."
Lieutenant Shigeru Sanada, a military cryptographer and CAD developer, had been stunned by my storage-swapping device prototype. He'd conceptualized something similar but struggled. A technical officer in Okinawa where mages often gathered made sense, given his expertise.
My original-story knowledge and Dad's device supply helped. I'd built an underground CAD workshop and training area beneath the garden, using [Copy] a perk replicating inorganic objects I perceive. Realizing it could create "something from nothing," I swore to limit its use. Dad nearly fainted when he saw the space, secured with decomposition magic and copied materials.
Mom scolded me "Consult us first!" prompting my finest elementary-schooler kowtow. I later bought equipment via FLT, reasoning it'd benefit my siblings too. Now, I handle CAD design underground, final tweaks in my room, partly for Shina's sake.