Sakura walked down the quiet street toward school, Riv perched neatly on her shoulder. To anyone passing by, it looked like a cute girl with a cute cat.
To Sakura, it felt like walking around with a talking stress machine.
"Riv," she sighed, "you said I need to collect all the cards before the world collapses. But how am I supposed to fight? I'm only fourteen."
"You have a card," Riv said. "That alone already makes you dangerous."
"Yeah, but—not really 'save the world' dangerous."
Riv flicked her forehead with his tail.
"That is why I must explain the rules."
Sakura straightened her posture.
"Okay. Hit me. But not literally."
---
Riv hopped down to the ground and faced her seriously.
"Every time you obtain a new card, Sakura, your body absorbs a fragment of its power. Even if you don't use that card, your base strength increases."
"Base strength? Like… stats in a video game?"
"Exactly."
Sakura blinked.
"…so collecting cards is basically leveling up?"
"Yes. Though some cards give more growth depending on their universe, abilities, or cosmic importance."
Sakura imagined herself getting gradually stronger until she could punch a boulder in half.
"…Okay that's actually kinda cool."
---
Riv circled around her feet.
"When you transform using a card, Sakura, you don't just wear the appearance. You temporarily become the character."
"That's good, right?"
"It is. But also dangerous."
Sakura felt a chill.
"Dangerous how…?"
"You inherit their instincts."
Sakura froze.
"So if I transform into someone… intense…"
"You might temporarily think like them."
Riv's tone was gentle, but firm. "Most characters are stable enough. But some are extremely violent, chaotic, or mentally unstable. Losing control is possible."
Sakura gulped.
"So… if I turned into a villain card—"
"You could become what the character originally was. Even if only for a moment."
Her eyes widened.
"Oh no.
That's horrible."
"And that," Riv said softly, "is why you must grow stronger. A stronger body and mind helps resist character instincts."
"Okay… noted. No transforming into psychopaths."
"Good rule."
---
Riv raised his tail like a teacher holding a pointer stick.
"Transforming with good intentions stabilizes peaceful or heroic forms. But if someone uses a card with hatred, envy, greed, or malice…"
He looked toward the sky.
"…the transformation strengthens."
Sakura shivered.
"You mean… if a bad guy uses a powerful card…"
"They become even more dangerous than the character they transformed into."
"That's terrifying!"
"Yes. Imagine someone full of hatred using a villain from a dark universe."
Sakura felt her stomach drop.
"That's literally nightmare fuel."
"Correct."
"And I have to fight people like that?"
"Only you can."
Sakura groaned dramatically.
"This is the worst magical girl contract ever."
Riv patted her leg with a paw.
"You'll be fine. Probably."
"'Probably' is not comforting!"
---
Just then, Riv's ears twitched.
"Sakura," he whispered, voice low, "we're being watched."
Sakura stiffened.
"W-watched? By what?!"
A cold wind drifted down the empty alley beside them.
A figure stepped out—someone around Sakura's age, but with a wild grin, shaking hands, and a glowing card clutched tightly.
"Sakura Yumine," he said, voice trembling with excitement.
"You're the girl who got the Sakuyamon card, right?"
Sakura slowly stepped back.
"How do you know my name…?"
"Everyone's been looking for the Chosen Collector. And now I found you."
He raised his card.
On its surface was the image of a monstrous creature—muscular, fanged, furious.
Riv whispered quickly, voice trembling:
"Sakura… that card is Unstable Class! It reacts strongly to negative emotions!"
Sakura's breath hitched.
"What negative emotions—?"
The boy's smile twisted into something ugly.
"I'll take your card… and your power…
Even if I have to break you to do it!"
The card in his hand burst into red-black light.
Sakura felt pure malice fill the air like poison.
"Oh no," she whispered.
Riv hissed.
"Sakura! Transform—NOW!"