Demon in Karasuno

The gymnasium of Karasuno High was thick with the scent of floor wax and the rhythmic squeak of sneakers against hardwood. However, the usual air of competitive spirit was clouded by a heavy sense of bewilderment. Coach Ukai stood at the center of the court, a crumpled official notice from the Miyagi Prefecture Volleyball Association clutched in his hand.

"A mandatory mixed-gender integration?" Takeda-sensei adjusted his glasses, reading over Ukai’s shoulder for the tenth time. "Every boys' team must register one female player as a permanent starter? This is... unprecedented."

"It’s an experimental initiative to bridge the gap in playstyles," Ukai grunted, rubbing the back of his neck. "But where the hell are we supposed to find a girl who can keep up with this pack of crows? Most of the girls' team players are already committed to their own season."

The team stood in a semi-circle, murmuring amongst themselves. Hinata was vibrating with excitement, his eyes shining at the prospect of a new teammate, while Tsukishima looked characteristically bored.

"I have a candidate."

The voice was cold, precise, and came from the one person who rarely spoke unless it was about a toss. Kageyama Tobio stood with his arms crossed, his expression even more serious than usual.

"You do, Kageyama?" Daichi asked, surprised. "Is she from a local middle school?"

"No," Kageyama replied, his gaze flickering toward the gym doors. "She’s been playing professionally in England for the last few years. She’s my sister. Mariam."

A collective gasp rippled through the gym. Tanaka and Nishinoya were suddenly inches from Kageyama’s face, their eyes practically turning into hearts.

"Kageyama! You have a sister? Is she beautiful? Does she like upperclassmen?" Nishinoya demanded, though his bravado faltered when he realized Kageyama’s sister would likely be taller than him.

"She’s coming back to Japan today," Kageyama continued, ignoring them. "She’s a Wing Spiker. But... just so you know, her style isn't exactly 'standard.'"

"What does that mean?" Hinata chirped, bouncing on his heels. "Is she amazing? Does she go *whoosh* and *bam*?"

"She goes for blood," Kageyama muttered under his breath, a shadow of genuine concern—or perhaps warning—crossing his face.

The heavy gym doors creaked open moments later. The sunlight from outside spilled across the floor, silhouetting a small figure. As she stepped into the light, the silence that followed was absolute.

Mariam Kageyama was tiny. She was even shorter than Nishinoya, a fact that made the Libero blink in disbelief. But what she lacked in height, she more than made up for in presence. Her dark chestnut hair flowed down her back, contrasted by a sharp, straight fringe that brushed her forehead. Her eyes were a deep, haunting violet—the color of a bruise or a stormy twilight.

She wasn't wearing a school uniform. She wore a black leather jacket over a tattered sports top and shorts, her knees covered in scars and fresh scrapes. But it was her expression that froze the room. She was wearing a wide, dangerous smirk that didn't reach her eyes—eyes that scanned the room like a predator evaluating a herd.

"Tobio," she said, her voice smooth but laced with a sharp edge. "You look as stiff as ever. Did you miss me?"

Kageyama sighed, his shoulders tensing. "You’re late, Mariam."

"The flight was boring. I needed to find a decent espresso before coming to this... rustic establishment," she said, her gaze landing on Hinata. She walked toward him, her movements fluid and predatory. She stopped inches from his face, looking up at him despite her stature. "And who is this? A tangerine? Or a mascot?"

Hinata turned bright red, his heart hammering against his ribs. Up close, she was breathtakingly beautiful, but she smelled like ozone and expensive perfume. "I-I’m Hinata Shoyo! Middle blocker!"

Mariam leaned in, her violet eyes narrowing. She reached out and flicked his forehead, hard enough to leave a red mark. "You’re cute, Sun-chan. I think I’ll keep you."

"Sun-chan?" Hinata squeaked, clutching his forehead.

"Alright, enough," Ukai stepped forward, trying to regain control. "Mariam, I’m Coach Ukai. Your brother says you played in England. We need to see what you can do. Put on a bib and join the B-side for a scrimmage."

Mariam’s smirk widened, turning into something truly feral. "Oh, Coach. I don't think you want me to just 'join.' I don't play games. I win wars."

She stripped off her leather jacket, revealing lean, corded muscle in her arms. She stepped onto the court, picking up a volleyball and spinning it on one finger. The way she looked at the ball wasn't with affection; it was with an obsessive, hungry intensity.

The scrimmage began. Mariam was a whirlwind of chaos. Her style was unlike anything the Karasuno players had ever seen. She didn't just jump; she launched herself with a reckless disregard for her own safety, twisting her body in mid-air to pull off angles that seemed anatomically impossible.

"Watch out!" Sugawara yelled as Mariam dove for a ball, her shoulder slamming into the floor with a sickening thud.

She didn't even flinch. She rolled, popped back up, and was already screaming for the set. Her knees were bleeding, the skin scraped raw from the friction of the floor, but she looked like she was having the time of her life.

"Kageyama! Set it to me!" she barked.

Kageyama didn't hesitate. He delivered a pinpoint set to the left pin. Mariam took off. Her vertical jump was staggering, allowing her to reach heights that defied her small stature. But it wasn't the height that was scary—it was the aim.

As the blockers—Tsukishima and Daichi—rose to meet her, Mariam’s eyes flashed. She didn't aim for the open space. She aimed directly at Tsukishima’s face.

The ball whistled through the air, a violent blur of yellow and blue. Tsukishima barely had time to move his hands. The ball grazed his temple with enough force to knock his glasses askew, slamming into the back wall with a sound like a gunshot.

"Oops," Mariam landed, her smirk never wavering. She wiped a drop of blood from a fresh cut on her cheek. "My hand slipped. Or maybe you’re just too slow, Four-eyes."

"Hey!" Tanaka shouted, stepping forward. "That was dangerous! You almost took his head off!"

Mariam turned her violet gaze on Tanaka. The sheer malice in her eyes made the hot-headed second-year freeze in his tracks. "In England, they called me the Demon. Do you know why? Because I like the sound a spirit makes when it breaks."

"Mariam, knock it off," Kageyama growled. "This isn't a back-alley match in London."

She turned to her brother, her expression softening into something strangely affectionate yet still twisted. She walked over and pinched his cheek hard. "Don't be a bore, Tobio. I’m just warming up."

She then turned her attention back to Hinata, who was watching her with a mix of terror and absolute awe. She walked up to him and wiped a smudge of dirt off his nose with a thumb that was stained with her own blood.

"What do you think, Sun-chan?" she whispered, her voice low and melodic. "Am I too scary for you?"

Hinata swallowed hard. He felt a strange pull toward her—a mixture of the fear she inspired and the undeniable brilliance of her play. "You... you’re amazing. But you’re going to get hurt playing like that!"

Mariam laughed, a sharp, melodic sound. "Hurt? Pain is just a reminder that I’m winning. If I’m not bleeding, I’m not playing."

She turned back to the court, her long ponytail whipping behind her. "Again! I want to see if the Captain can actually dig one of my serves, or if I have to carry this whole murder of crows on my back."

The rest of the practice was a blur of high-tension plays. Mariam played with a suicidal intensity, her body becoming a map of bruises and scrapes. She targeted the opponents relentlessly, her serves curving at the last second to aim for chests and shoulders rather than the floor. It was psychological warfare as much as it was volleyball.

By the time practice ended, the team was exhausted, not just physically, but mentally.

"She’s... she’s something else," Daichi panted, wiping sweat from his brow. "She’s got the skill of a pro, but her temperament is..."

"A nightmare," Tsukishima finished, adjusting his glasses. "She’s a literal hazard."

Kageyama stood by the equipment room, watching his sister. She was sitting on a bench, haphazardly wrapping a bandage around her bloodied knee, humming a dark tune to herself.

"She’s always been like this," Kageyama said quietly to Sugawara. "She loves too hard and fights too hard. In England, she nearly got banned because she kept targeting the other team’s star players until they couldn't play anymore. She doesn't see opponents as people. She sees them as obstacles to be demolished."

"And what about us?" Sugawara asked, worried.

"She’ll die for her team," Kageyama replied. "But heaven help anyone who stands on the other side of the net."

As the sun began to set, casting long, orange shadows across the gym, Mariam stood up and slung her bag over her shoulder. She spotted Hinata heading toward the door.

"Sun-chan!" she called out.

Hinata stopped, turning around. "Yes, Mariam-san?"

She walked up to him, her predatory smirk replaced by a look that was almost... soft. She reached out and ruffled his orange hair, her touch surprisingly gentle despite the calluses on her fingers.

"You have a lot of light in you," she murmured, her violet eyes searching his. "It’s disgusting. I want to see how long it takes for me to dim it, or if you’ll end up burning me instead."

Hinata blinked, confused but emboldened. "I won't dim, and I won't burn you! We’re teammates now! We’re going to Nationals together!"

Mariam stared at him for a long moment, then let out a short, huffed laugh. She leaned in and kissed his cheek—a fleeting, stinging contact that left Hinata paralyzed.

"We’ll see, Sun-chan," she whispered against his ear. "But remember... I don't play nice. And if I fall in love with you, I’ll love you until there’s nothing left of either of us."

She pulled away, her dangerous smirk returning as she walked toward her brother. "Come on, Tobio. Buy me dinner. I’m starving after dealing with all these amateurs."

Kageyama grumbled but followed her out. Hinata stood in the middle of the gym, his hand pressed to his cheek, his heart racing at a speed that had nothing to do with cardio.

Karasuno had gained a new player. They had gained a weapon, a demon, and a girl who played like the world was ending.

The road to Nationals had just become significantly more violent.