Chapter Text
The Simulation Club room at Seiran Academy was, in theory, a haven for enthusiasts of all things vehicular—flight sims, tank sims, naval sims, you name it. In practice, it was a high-decibel warzone.
"Angle your hull, you absolute donut!"
"Radar lock! Radar lock! He's notching—Fox-3 away!"
"Who let a premium Level 1 into top tier?!"
Nami Hoshino stood frozen in the doorway, her application form crinkling slightly in her grip. Towering PC rigs with liquid cooling and more RGB than a festival lit up the room like a sci-fi battle station. Three- monitor setups. Flight sticks. Throttle quadrants. A faint haze of humidity and sweat and overclocked processors. She could feel her casual, naval-loving soul recoiling like a startled sea slug.
This... this is the Simulation Club?
She’d expected a few middle-aged strategy nerds discussing rudder shift. Not an e-sports thunderdome. Her gaze swept the room, looking for any escape route—or at least a quiet corner where she wouldn’t be screamed into submission.
That’s when she spotted the lounge area, tucked past a row of intimidating black soundproof cabins. And in that lounge, at a low kotatsu-style table, sat the smallest girl Nami had ever seen in a high school uniform.
The girl was drowning in a fluffy, cream-colored sweater two sizes too big for her. Cotton-candy pink hair was tied into two soft, low pigtails that spilled over her shoulders. A tiny juice box with a bendy straw sat beside a pink notebook, into which she was very seriously drawing a picture of a plump, cheerful bird. Everything about her—the slight frame, the rounded cheeks, the gentle way she held a glitter pen—radiated an aura of peaceful, marshmallow-sweet innocence.
Nami’s defensive instincts, dormant until now, flickered to life. Oh no. They left a literal angel unattended in a warzone.
She weaved past a gesticulating pair of third-years arguing about volumetric shell mechanics and made a beeline for the low table.
The pink-haired girl looked up just as Nami’s shadow fell across her drawing. Big, amber-brown eyes blinked once, twice, then widened with unguarded curiosity.
“Um, hello!” Her voice was soft as a breeze through cherry blossoms. “Are you here to play the boat game?”
Nami blinked. “The... boat game?” She looked down at her phone, where an anchor-shaped charm dangled from the case. “Oh! You mean Naval? War Thunder Naval?”
The girl nodded, the tiniest of smiles creeping onto her lips. “I saw your anchor. It’s very pretty. I thought… maybe boats.”
It was such a small, sweet observation, and something in Nami’s chest immediately melted into a puddle. She crouched down to the girl’s eye level.
“You’re incredibly sharp! Yes, I love Naval battles. What’s your name?”
“Koharu,” the girl said, almost shyly. She set down her glitter pen with great care. “Just Koharu.”
“Koharu... that’s adorable. I’m Nami. Nami Hoshino. First-year.” She gestured at the club chaos behind her. “Are you... a member here?”
Koharu nodded earnestly. “Mm-hm. I’m a second-year. I usually just... sit here, though.”
“A second-year?” Nami’s voice pitched up in disbelief. She studied the tiny figure—the way the sweater sleeves hung past her fingertips, the jelly-sandaled feet barely touching the floor. “You? No way. You look like you’re in middle school!”
Koharu giggled, a sound so light it could have been wind chimes. “I get that a lot.”
A fresh explosion of noise erupted from the main rigs—someone had just been team-killed on takeoff, and the resulting argument was apocalyptic. Nami instinctively shifted her body to shield Koharu from the verbal shrapnel.
“Hey,” Nami said, lowering her voice conspiratorially, “do those loud guys ever bother you? It’s like a pack of howler monkeys in here.”
Koharu glanced toward the big rig area, then back at Nami. “Not really. They’re very... focused. I just stay over here and draw my birds.”
She slid the pink notebook toward Nami. The bird was a round, fluffy fellow with a topknot, standing proudly on one leg. It was, frankly, a very good bird.
“That’s the cutest thing I’ve ever seen,” Nami admitted. She felt a fierce, instant sisterly protectiveness bubbling up. A second-year who looked like a plush toy, sitting quietly with her juice box while the upperclassmen screamed about damage models? Unacceptable.
“Listen, Koharu-chan,” Nami said, putting a hand on her own chest. “I just joined today, and I’m probably terrible compared to all these... competitive maniacs. But from now on, you stick with me, okay? I’ll be your big sister in the club. If anyone so much as raises their voice near you, I’ll—well, I’ll deploy a smokescreen and we’ll retreat to the cafeteria.”
Koharu’s eyes went wide, starrier than before. “Big... sister?”
“That’s right! Big Sis Nami of the High Seas. I may only play at BR 5.7, but I’ll protect you from all the scary, loud, sweaty top-tier players.” She grinned and gave a thumbs-up. “That’s a promise.”
Koharu stared at her for a long, unreadable moment. Then her cheeks lifted in a smile so warm and genuine it could have powered the whole school. “Okay, Nami-oneechan. I’ll be in your care.”
Nami-oneechan. The honorific wrapped around Nami’s heart like a warm blanket. She barely resisted the urge to scoop Koharu up and feed her homemade onigiri.
A loud clatter from the far end of the room broke the spell. Club president Sasaki, a bespectacled third-year with the eternally tired face of someone who managed both a server database and teenage egos, clapped his hands.
“New members! If you haven’t signed in, please see me by the soundproof cabins. We’re assigning slots for open-play hours and sound-cabin rotations. Ranked players, your cabin keys will be distributed this evening.”
Nami glanced at the row of glossy black soundproof cabins lining the back wall. Each one had a frosted glass door and a tiny LED status light—most were dark, but one in the corner glowed a faint, pulsing blue.
“What’s the deal with those?” she asked Koharu.
“Um, the best players use them. So they can focus without anyone peeking at their screens.” Koharu’s voice was still soft, but Nami thought she detected a flicker of something else. Pride? No, that didn’t make sense.
“Pfft. Sounds lonely,” Nami said, standing up. “I’d much rather play out here with you. Who needs a soundproof box when you’ve got good company?”
Koharu’s expression settled back into its usual gentle sweetness. “Mm. I like it out here with you too, Nami-oneechan.”
“Alright, I’ll go register, and then I’ll bring my laptop. You can watch me captain my heavy cruiser. I’ll even teach you about ammo-racking—oh, that’s when you hit below the waterline and—”
A violent "BING" from the main rigs interrupted her, followed by a howl of despair: “HOW DID HIS SHELL GO THROUGH MY MANTLET, THAT’S NOT EVEN PHYSICALLY—"
Nami flinched. Koharu just took a calm sip of her juice box.
“Yeah,” Nami said firmly, “you’re never going near those guys without me. C’mon, little spring, let’s get you a cookie later.”
She ruffled Koharu’s hair—soft as spun sugar—and strode off toward President Sasaki, already feeling more confident. She had a role in this chaotic club now: guardian of the cutest creature in Seiran Academy. Not a bad first day.
Behind her, Koharu watched Nami’s back retreat. Her innocent smile didn’t waver, but a small, quiet shift came over her posture. Her shoulders straightened a fraction. Her gaze, still doe-soft, sharpened at the edges with an intelligence that had nothing to do with glitter pens and plump birds.
President Sasaki, having finished with Nami’s registration, happened to glance her way. He made no move to approach—not yet—but he tilted his head in a silent, respectful acknowledgment.
Koharu picked up her pink notebook and gently closed it. On the back cover, half-hidden by a strawberry sticker, was a small custom logo: a stylized scythe forming the curve of a wave, with the initials S.R. inscribed beneath.
She slid the notebook into her oversized sweater pocket, finished her juice box with a quiet slurp, and gazed at the pulsing blue light of her own soundproof cabin—the one in the corner, waiting for nightfall.
Then she resumed her perfectly angelic smile and hummed a lullaby to herself, a tiny, harmless second-year who definitely didn’t know the trajectory drop of every anti-aircraft shell in the game.