Itsuka Kendo was sore all over her body, but her smile never faltered since returning from school.
Yesterday's training had been fruitful. She and Ai had managed to pull a brand-new Quirk out of thin air.
It wasn't Big Fist.
It was Tremor.
Itsuka wanted to go to her Quirk doctor and kick him in the balls for not doing his job properly. With how much he charged her parents for every appointment, he should've at least tried a bit harder.
But if Itsuka wanted to kick her doctor's ass, she also wanted to United States of Smash herself for being such a fool. She was the one who'd neglected her Quirk for over ten years.
Once the excitement of having a Quirk that just enlarged her hands had died down, people started to undermine its potential.
And Itsuka had unconsciously done the same.
For over ten years, she let the voices around her get into her head. On the outside, she was a strong-willed girl who wouldn't back down from any challenge.
But on the inside, she was being chipped away—piece by piece—by her own insecurities. Every time her confidence peaked, it only took one moment—one incident—to make her second-guess herself. And then, she'd start to crumble under the pressure.
All because everyone told her she couldn't do it with a Quirk like hers.
It wasn't flashy enough to be a hero.
Not strong enough to save anyone.
Her Quirk was unladylike—just like her.
She wasn't enough.
Those were the words whispered, spat, and thrown at her by those who never believed in her.
And somewhere along the way… she started to believe them too.
So, she decided to focus on improving her body, her fighting style, and her combat skills—things she could change and improve.
Unlike her Quirk, which she believed had already reached its maximum potential. That was it. No more growth. No more power.
She gave up on it.
Itsuka rolled onto her bed, the ache in her arms a painful reminder of how foolish she had been. She needed someone else's help just to understand how to use her own Quirk.
Someone who could see through it—see its strength and potential.
—Yesterday—
"D-Did you just rename my Quirk!?"
Itsuka didn't know whether to be offended that someone renamed her Quirk like it was a pet… or flattered that he thought it was stronger than she ever believed.
Ai chuckled, like he hadn't just asked Itsuka to punch him in the throat for making such a big decision for her without even asking.
He walked around her while checking her body, his golden eyes darting to the muscles in her arms and legs.
"It was just a funny theory at first," he said. "Your Quirk reminded me of someone I know. He can create earthquakes just by vibrating his hands. Nothing special—his Quirk just makes his hands move up and down really fast. And voilà—earthquake."
Ai stepped closer to her side and looked up, asking politely, "May I?"
Itsuka nodded, too focused on her Quirk to realize she'd just agreed to let a guy feel her muscles. The realization only hit her afterward—but by then, it was too late.
She watched as Ai ran his fingers along her arm, tracing the curve of her bicep and the firmness of her pecs with quiet curiosity.
"After I saw you during the Quirk Apprehension Test, the idea started playing in my head," Ai said, rubbing the back of his neck. "Imagine if you could change the size of your hands repeatedly at the same speed you used to punch that robot. Man, you'd probably start vibrating yourself."
He snorted at his own dumb thought.
Itsuka didn't laugh. Instead of finding the thought ridiculous, she actually realized she'd never tried to repeatedly change the size of her fists. She always just enlarged them, punched something, then deactivated the Quirk.
"Then Eve bullied me into helping you train your Quirk, so I figured I might as well check for myself if there was any truth to my theory. And tadaaa! Turns out your great-great-great-granddaddy had a vibration-type Quirk."
Itsuka's face flushed at the reminder. Ibara had bullied him into training with her—threatening to ban him from going to Comiket. He'd nearly cried at the time.
"So yeah," Ai continued. "Let's try it out. If it doesn't work, we'll just focus on improving your shockwave punch."
Itsuka looked at the boy as he stepped away from her, standing at a distance with his hands on his waist.
"Okay, Kendo—"
"Itsuka," she interrupted, cutting him off. "Just call me Itsuka. You've been helping me, and I call Ibara by her first name, so let's drop the formality and stuff."
Ai smiled and nodded.
"Okay, Itsuka. Then just call me Ai."
She smiled back. "Sure, Ai."
Ai cleared his throat and continued.
"So, like I was trying to say… let's start with increasing and decreasing the size of your hand repeatedly—as fast as you can."
Itsuka nodded, stretching her arm out to begin activating her Quirk, just like Ai told her.
She took a deep breath and readied herself. Just like before. Let it grow and shrink without controlling the speed.
-VWOOP-
-VWIP-
"Guahh!"
....
"So doing it at full size is a no-go at the moment, huh?"
Ai and Itsuka were back in the gym after she had ragdolled herself across the room. The backlash from growing and shrinking her hand too rapidly had launched her into the wall.
Now, Itsuka was glaring at Ai with little amusement. The two had just returned from a quick visit to Recovery Girl. Luckily, her injuries weren't serious, but she wasn't allowed to use her right hand for training until tomorrow.
"So what now?" Itsuka asked, trying to ignore her aching arm—or the big bump on Ai's head from when Recovery Girl smacked him with her cane for being reckless.
"Let's start in tiny portions," Ai said, holding up his hands to demonstrate the size he meant. "Like this. Vibrate your Quirk starting at this size."
"There's a problem," Itsuka replied. "Unlike my maximum size, how do I stop it at the right size?"
She grew her hand and stopped it at the size Ai had indicated.
"Can't you, like, put a mental pause on it? Like, 'This size is my max right now'?" Ai suggested while nursing his bump with a cold towel.
"I've never tried that before, but… let me try."
Itsuka created a mental limit of how big her hand would grow. She focused—not on the speed this time, but on the boundary. And for the first time… it worked. Her hand stopped exactly at her mental cap. Her eyes widened in surprise.
"Dude, are you a time traveler or something? Did we meet in the future? How the hell are you figuring this stuff out about my Quirk?"
Ai snorted at Itsuka's comment. "I'm not a time traveler. If I was, you'd see me walking around with big 'I-know-something-you-don't' energy, probably surrounded by my harem."
"That sounds like an anime plot," Itsuka deadpanned.
Ai burst out laughing, wiping tears from his eyes. "Because it is!"
After calming down, he added more seriously, "Believe it or not, Quirks are way more mysterious than Quirk science claims. So treat your Quirk like an extension of your soul. I swear, it makes a difference."
Itsuka stared at him, unsure whether he was being serious or just quoting anime again. She decided to save the judgment for later and gave the vibration trick another shot.
She lifted her left arm and focused. A mental break—5% of her usual max hand size. Then, she rapidly grew and shrank her hand.
VWOOP-
-VWIP-
VMMMMMMMM
Itsuka slowly opened her eyes. Her whole left arm felt... strange. Not just her hand—her entire arm was vibrating at high speed, looking like it was blurring out of existence.
"Can you move it?" Ai asked, eyes gleaming with fascination.
Itsuka tested it—bending her elbow, rotating her wrist. It worked, though it felt weird, and she could already feel the strain of holding the vibration for too long.
"Let's try punching something."
Ai ran to the corner of the room, dragging over a punching bag and setting it up in front of her.
"Go ahead—punch it."
She nodded, cocked her vibrating left arm back, took a deep breath, and—
VMMMMMMMM
BOOM!
The moment her vibrating fist connected with the punching bag, a shockwave exploded between her fist and the surface. The bag was launched several feet into the air before the shockwave tore it apart midair, shredded by the sheer force and wind pressure.
Itsuka's jaw dropped.
That was… like one of All Might's Smashes. Virginia? California? She wasn't sure—but it was hella cool. And she did it.
She stopped the vibration and stared at her hand.
She didn't know what to think.
She didn't know what to say.
She just looked at it.
And then—
Tears welled up in her eyes.
"Ai said Quirks are the extension of our soul, huh…"
"I'm sorry."
"I'm sorry."
"I'm sorry."
She dropped to her knees, cradling her aching arm to her chest, and stayed there for a while—apologizing for something others might find strange.
But that didn't matter.
Because to Itsuka, her Quirk deserved an apology—for being ignored, misunderstood, and underappreciated for years.
In the distance, Ai was silently sweeping the floor, sensing that today's Quirk training session was officially over.
End of Chapter 23