High School DxD – "Shadow Level-Up!"
Kuoh's spring rain smelled of wet cedar and ozone, drumming lightly on the academy's tiled roof as Kazuki Ren slid the window shut behind him. Evening classes had ended, but Rias's message—penned in elegant violet ink—had redirected him to the deserted kendo gym: "Come alone. Wear something you can ruin." That last line still curled mischievously behind his eyes.
He'd chosen a black track-suit and fingerless gloves, hair tied to keep silver strands from blinding him mid-dash. Inside, the gym lights glowed half-dim to save electricity, turning varnished floors into a mirror for amber fixtures overhead. Kiba awaited, wooden bokken balanced on his shoulder; Koneko lounged on the wall bars munching apricot buns. Rias, in crimson PE shorts and an oversized Kuoh hoodie, paced barefoot across the center line.
"Tonight," she began, voice carrying just enough authority to echo, "we measure how fast you're growing." A sideways smile followed. "And whether my club can still catch up."
Kazuki inclined his head. "Parameters?"
"Three rounds. Wooden weapons only, no magic circles, no lightning, no shadows bigger than a house-cat,"—this with a pointed glance at the darkness drifting lazily behind his heels—"and no lethal intent. If Kiba lands first strike, he wins. If you land first, you win. After each bout, you sprint the track with Koneko wearing weight vests. Stray hunts aren't chess—they're stamina wars."
Kiba tossed him a second bokken. Kazuki caught it, testing grip. It felt feather-light compared to the iron pipe he'd grown fond of. He flicked a salute. The hybrid aura inside him—fallen luminance braided with devil ember—pulsed evenly; neither side flared, proof that yesterday's breathing drills worked.
Koneko rang a handheld bell. Wood cracked as both swords met mid-air. Kiba's style was textbook iaido purity—explosive first step, lethal economy. Kazuki's was instinctive street-kinetics, a touch of fencing feint, a ghost of capoeira pivot. First exchange ended in near-misses: Kiba's thrust traced Kazuki's collarbone; Kazuki's counter-slash shaved a hair from Kiba's bang.
Kazuki let his perception widen. AGI 11 translated into fluid footwork; the floor seemed generous with friction, allowing sharper stops. He slipped inside Kiba's guard, shoulder-checked gently, and tapped bokken tip to the knight's sternum.
Koneko's bell tinked. Round one; Kazuki.
Second bout, Kiba grinned ferally and upped pace. Wooden blades blurred three, four strikes per heartbeat. Sweat peppered the air. Kazuki parried high, ducked low, stepped past a diagonal slice… and felt his rear foot skid on faint sweat sheen. Kiba seized the opening—pommel kissed Kazuki's ribs, blade kissed his shoulder. Bell. Round two; Kiba.
They jogged the track next, rain misting through open bleachers. Koneko perched on Kazuki's back like a stone gargoyle, whisper-light for her size but the 30-kilo vest on his chest burned lungs. He synced footfalls with devil heartbeat—push on the demonic heat exhale, pull oxygen on angelic cool inhale. By the sixth lap the burn smoothed into rhythm.
Back in the gym they squared for round three. Rias leaned against wall mats, arms crossed, keen eyes recording data only a clan heiress would note. Thunder murmured distant approval through the roof.
Bell.
Kiba opened with a low feint; Kazuki ignored the blade and watched hips instead. He twisted, letting the strike graze fabric, then let go of the bokken entirely—hands snapped outward, palm meeting Kiba's wrist, redirecting momentum. As sword clattered, Kazuki pivoted behind, tapped two fingers to spine—
Bell. Round three; Kazuki.
Wood retrieved, sweat wiped, cool-down stretches commenced. Kiba offered knuckles; Kazuki bumped them, respect plain in the shared grin.
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Stray Patrol: Week-long Sweep
Rias's new strategy distributed small teams across Kuoh's outskirts five nights in a row, targeting rumor clusters before strays could nest. Kazuki partnered mostly with Rias herself—ostensibly for evaluation, though the walks morphed into easy conversation broken only by quick skirmishes.
Night One – Railway Yard
Sheet-metal wind rattled like percussion. Two mantis-type strays ambushed from storage cars; Kazuki becalmed one with a pipe thrust through thorax, Rias erased the other with a crimson sphere of Power of Destruction that left ozone hanging heavy. Debrief on a freight container roof turned into stargazing. She pointed constellations; he countered with old-Earth myths. Laughter echoed off boxcars until midnight curfew chased them home.
Night Three – Riverside Park
Moonlit fog hugged water; a lanky hound-devil stalked joggers. Kazuki's shadow Arachnid Knight netted it while Rias shielded civilians with wide-area gravity fields—her control improving under pressure. After cleanup they shared canned coffee from a vending machine. Rias teased his sweet-tooth; he pretended outrage, flicked sugar packet at her, missed on purpose. She caught it anyway—fast hands beneath dignified veneer.
Night Five – Shuttered Mall
Final patrol brought a tougher fight: four stitched-together homunculi armed with rusted machetes. Rias took two, Kazuki two. Shadow Soldier soaked first blows, allowing Kazuki to slide beneath and hamstring creations with a utility knife. Stray fragments tried fusing—a crude necromancy trick. Kazuki exhaled cold will; the fragments froze, letting Rias vaporize them clean.
Post-battle, breathing hard amid mannequin debris, Rias placed a hand on his forearm. "You dance with danger as if it promised music." Her tone held equal admiration and caution.
He shrugged, pulse still rapid. "Danger keeps tempo honest."
Purple motes from slain strays drifted up—+34 XP—nudging his total toward the midway mark to next ability. He dismissed the glow before Rias could suspect a tell-tale reflection in his eyes.
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Sunday – Library Afternoon
Classes paused for the weekend, but Rias invited Kazuki to Kuoh's old library "for research." Shelves towered cathedral-high, dust dancing in shafts of warm light. They occupied a corner table, ancient grimoires spread like wings. Officially they hunted lore on hybrid aura harmonics; unofficially they kept drifting off topic—favorite desserts, schooling differences between the Underworld and human world, the absurdity of Kuoh's dress-code skirt length.
At one point Rias leaned across to tug a spider web of parchment nearer; her fragrance—rose and library musk—briefly drowned Kazuki's inner equilibrium. He steadied breath. Devil heat flared; fallen chill tempered it. Balanced.
"Your control is smoother," she noted, fingers brushing the pulse at his wrist. "I can barely feel the clash inside you now."
"Practice." He tapped the grimoire diagram of twin energy spirals. "And a good teacher."
She blushed faintly but did not pull away. "Careful, flattery is expensive."
"I can afford the luxury." The words escaped before caution. Yet speaking them felt right.
Minutes later, when they rose to shelve tomes, her hand lingered a heartbeat longer in his. An unspoken understanding settled—soft as dust on old leather but harder to ignore each time their eyes met.
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Shadow Progress
That night, alone on his apartment roof, Kazuki reviewed gains. XP total: 302 / 350. Close. He summoned both shadows. Soldier knelt; Arachnid Knight towered, eight chitin blades folded. He envisioned a third form—something aerial—but extraction required a fresh corpse. Patience.
He practiced Shadow Step—new instinct that let him slip through a puddle of darkness and emerge three meters away. The motion felt like diving into oil, re-surfacing in dry air—a vertigo jolt but quicker than a hurdle sprint. Five reps left him dizzy yet giddy.
Rain broke again, heavier now. He dismissed shadows, let the storm soak track-suit cotton, face upturned. Lightning flickered; for an instant his silhouette etched against night sky, black wings teased at shoulder-blades—an illusion of pending evolution.
Somewhere below, Kuoh slept unaware that strays vanished faster each week; unaware that its crimson-haired princess and silver-haired hybrid had begun synchronizing battle rhythms and library whispers alike. Twenty chapters of solitary grinding lay ahead, but Chapter Four closed on the quiet promise that power wasn't the only bar filling steadily—so was trust, and something gentler he refused yet to label.
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End of Chapter 4