Chapter 1: With Power Comes…

When Izuku arrived at Aldera High School on Monday morning, his mind was focused on testing his new quirk. There was no lack of test subjects here, though if possible, he’d want to limit his tests to people he could keep a close eye on just in case. The only problem was that Izuku Midoriya wasn’t exactly a social butterfly.

Unfortunately, even with his new past and physique, he was still the butt of many jokes being the only quirkless student in his class. His less-than-intimidating visage did little to deter the mean-spirited boys from trying to ridicule his dream of being a hero. Though, he did note that in his memories, fewer girls would join in on the bullying, granted he hadn’t a clue why. Regardless, the green-haired student didn’t have many classmates close to him he could reasonably get close enough to test on.

'I need to figure out how this quirk works and if I can control it,' Izuku thought as he sat at his desk. He watched as his fellow students talked and interacted with one another, scanning the room for a potential target. His eyes landed on a boy he had never really interacted with before, a quiet student who often sat at the back of the classroom. Izuku recalled that the boy had a simple quirk that could make his face glow, though he was embarrassed to use it since it highlighted his acne.

With his heart pounding, Izuku focused on the boy, trying to will a minor change into being. ‘Perhaps clearing up the blemishes on his face to help his self-confidence? That could work.’

He concentrated, feeling the familiar pull within him, but nothing happened. The boy remained unchanged, going about his morning routine oblivious to Izuku’s efforts.

'Or not…' Izuku sighed, feeling a mixture of disappointment and curiosity. 'It worked for Mom and All Might. So what would be different? Do I maybe need to know the person better for it to work? I don’t know…'

Just as Izuku had the thought, he heard the familiar sound of stomping feet. Izuku gulped, dreading this moment ever since the incident a few days ago. ‘Oh boy, he’s here.’

Katsuki Bakugo, his former childhood friend, was making his way through the classroom, aggressively ignoring Izuku as he headed to his seat. Bakugo's usual scowl was firmly in place, and he radiated his typical explosive energy. Izuku could tell that the blonde was holding back from saying something to him, and he had an idea why.

Just three days ago, the two had been in a rocky encounter with the slime villain. Contrary to Bakugo’s expectations, the first person to make a real attempt to save him was none other than the quirkless nerd he had bullied for years. It made sense to Izuku that the blonde couldn’t express his gratitude normally, so ignoring him was likely his best option. That was fine, though; that was just how Katsuki Bakugo was to him. They were once best friends, though Izuku still didn’t understand why they drifted so far apart.

Izuku watched him, pondering. 'Well, if it only works on people I have a connection with, then Kacchan might be the perfect test subject,' he thought. Despite their rocky relationship, Izuku knew Katsuki perhaps better than anyone else at their school.

Summoning his courage, Izuku focused on the explosive blonde. He thought about something small he could change, something that wouldn’t be immediately noticeable but would still prove his theory. 'Maybe I can make him a little calmer or less angry,' he mused, concentrating on the idea.

He felt the pull within him again, stronger this time as if his quirk was recognizing the connection between them. Izuku’s eyes widened; It was actually working. He tightened his focus, concentrating on the idea of making Bakugo a nicer, maybe calmer person. But how far should he go? Izuku didn’t want to change who Katsuki Bakugo was completely. Regardless of how he treated him, Bakugo was still someone he looked up to. At least in some regards.

Izuku focused on a different avenue then: his parents. Mitsuki and Masaru Bakugo were almost complete opposites in some ways. What if he took their best qualities and passed them onto their son? Mitsuki’s energetic, bombastic nature and Masaru’s level-headedness and temperament? That surely would make Katsuki Bakugo the best version of himself.

As the idea for the change began to finalize in form, a final intrusive thought suddenly bubbled up in Izuku’s mind. 'It would be nice if he stayed a bit more like his mom, though.'

Now that he was paying attention to his quirk, he felt a powerful surge of energy coursing through him. Izuku winced as he felt the pull of his quirk stronger than ever before. When his sight cleared, he gasped at the sight before him.

Katsuki Bakugo was no longer sitting in his seat. Instead, a fit woman with sharp features and messy ash-blonde hair sat in his place. Her expression was a mix of irritation and concern as she looked at Izuku. At a glance, he could see that she was softer yet still had her underlying fiery spirit.

Katsumi Bakugo’s eyes narrowed as they bored into his own. "What’s with the staring, nerd?" she huffed, though there was a noticeable blush on her cheeks.

Izuku's heart raced. 'What the hell happened? Did I just change Kacchan into a girl!?' Panic set in, and he tried to focus on changing her back. But the more he tried, the more he felt a strong resistance, almost like his quirk was pushing back against his efforts.

He strained harder, and much like how he attempted to change his mother a second time, a sharp pain shot through his head. The **** of the blowback sent him tumbling out of his chair, clutching his head in pain.

Katsumi’s eyes widened in alarm. "Deku!" she exclaimed, rushing over to his side. Her voice, though still gruff, carried a note of genuine concern. She knelt beside him, her hands hovering uncertainly before gently grabbing his arm. "You idiot, what happened? Can you stand?"

Izuku winced, trying to get his bearings. "I... I'm fine, just... just a headache."

"Fine, my ass," Katsumi muttered, pulling him to his feet with surprising strength. "Come on, we’re going to the nurse's office."

The classroom watched silently as Katsumi half-dragged, half-supported Izuku out the door. No one commented on the sight; to them, this was just another day of Katsumi dragging her best friend around. In fact, it was so common that as the two left the room, Izuku could hear murmurs about the “couple” being at it again.

Once in the nurse's office, Katsumi helped Izuku onto a bed, her brow furrowed as she did so. The tomboy looked around and clicked her tongue as she commented on the lack of nurses.

“I swear, are they always on a break or something?” Taking matters into her own hands, the explosive girl perused the medical cooler and pulled out an ice pack. Rushing over and placing on Izuku’s bewildered head, the girl finally spoke directly to him. "Alright, talk. What the hell was that?”

Stunned by this turn of events, Izuku quickly tried to collect his thoughts. New memories of the girl standing before him rushed into his head. The past of a raging bully was quickly being combined and overwritten with the memories of a teasing and reckless tomboy who hadn’t left his side since they were children. Not once had the girl done anything purposely malicious toward him, unlike her male counterpart. If anything, the two’s relationship couldn’t be more different than before. It wouldn’t be outlandish to say that the girl holding ice to his bruised noggin was his closest and best friend.

'Kacchan... I- This isn’t what I meant to do at all! How did this happen?' Izuku thought as he lay silently under his friend's ministrations. He felt a swirl of emotions as guilt and shock flooded him. He recalled how he made the change and what he actually wanted done. An epiphany hit him; his last thoughts were of making Bakugo more like his mom. 'I didn’t mean that literally! I mean… she’s nicer but… This is so wrong! I can't even change her back. What am I going to do…'

Rolling her eyes at the lack of a response, Katsumi leaned closer, her sharp features softened by concern. "You look like you've seen a ghost, Deku. What's going on with you?"

Izuku swallowed hard, his cheeks warming as he formed a response. "I... I just had a bad headache. I’m okay now, really."

Katsumi narrowed her eyes, clearly not convinced. "You suck at lying, Deku. Fine. Just rest for a bit, alright?"

The nerd nodded his head and continued to lie there, trying to make sense of everything. Katsumi stayed by his side, her expression still soft as she looked at him. "What, you push yourself too hard working out, you himbo? God, I swear you have more muscles than brains sometimes."

Every word further solidified the difference between now and before. Katsumi wasn’t picking on him. She was teasing him. Izuku could feel the warmth and concern from every sound out of her mouth. Going along with the excuse, Izuku managed a weak smile. "You got me… You know I have to if I’m going to keep up with you."

Katsumi smirked, a playful glint in her eye. "Keep up, huh? Good luck, dork. You’re looking at the future number-one heroine. With me around, you’ll have to work extra hard."

The way the blonde puffed out her chest and posed as she said that drew Izuku’s attention to a rather obvious result of his best friend's change. Katsumi Bakugo was hot. The girl was the epitome of a tomboy, yet he could tell that there were distinct feminine qualities she kept up.

“You’re staring again, Nerd.” The sporting girl grinned and leaned in closer, her face inches from his, causing Izuku's heart to skip a beat. "You know," she said, her voice dropping to a teasing whisper, "if you needed some attention, all you had to do was ask."

Izuku's face turned bright red, and blood rushed southward. The young adult stammered as he moved to adjust himself, "I-I uh…"

Leaning back, the girl chuckled to herself before catching something in her peripheral. She watched as the boy tried and failed to hide the activity in his pants. Activity that caused the blonde to grow rosey herself. “Do you have a…?”

Izuku shot upright instantly. “It’s not like that! I uh- huh?”

Before Izuku could defend himself, Katsumi stood up and marched over to the door of the nurse's office. Izuku watched in confusion as he heard the lock to the door click. “Kacchan, what are you-”

“Y-You can’t go back to class like that, right?” The girl interrupted, her face almost as red as his own. “H-Hurry up, take care of it before the nurse gets back.”

Izuku was stunned silent. ‘What in the world did she just suggest!?’

Time froze between the two, only the ticking of the wall clock adding any semblance of sound. Thoughts raced in Izuku’s mind. His former bully was now suggesting that he… ‘take care of himself’ in front of her. He wanted to scream. ‘What the hell did I change!?’

While the verdant boy sat conflicted, irritation began to boil within the ash-blonde girl. “Are you going to do it or not? We don’t have time!”

Izuku’s head pounded. For the first time since this affair began, Izuku was the one who started to be frustrated. He didn’t ask to be here! Sure, he may have changed her to be like this, but it wasn’t his fault he was in this state. But it was his reality, stuck in a room with his best friend while hard as a diamond.

‘How do I get out of this? She’s completely serious.’ The boy lamented, hearing the tapping of the girl's foot echo through the room. But then an epiphany struck. ‘I got it!’

“Look, my head is pounding… So… If you’re so concerned, why don’t you take care of it yourself?” Izuku cheered internally. ‘Ha! She’ll back down for sure now. Then we can get back to-’

“Fine.” One simple word ground everything to a halt.

“Huh.” Looking up into his friends' eyes, all he saw was a rosy yet serious face. She wasn’t joking.

“I said fine… Now scooch over.” Before the boy could react, the girl crossed the distance between them and plopped beside him on the nurse's bed. She then reached out and gripped his crotch.

“K-Kacchan!” Izuku squeaked out at the sudden pressure.

Katsumi’s face was atomic red. “S-Shut it, nerd…”

Continuing, Katsumi began to quest her hand along the hardening length beneath the boy's trousers. It was the first time she had ever done anything even remotely close to this, and she was absolutely shocked by the sheer size of the mass hidden in her best friend's pants. Compared to what she’d seen in her ‘research,’ this behemoth easily surpassed the length of her hand. She gulped. “No way you’re hiding this… thing.”

Unsure of what to do, Izuku fought back the urge to leap up and escape. All he could do was focus on the sensation the girl was bringing him. Meanwhile, the girl finally found the tip of the monster and began to rub the ridge hidden beneath.

Izuku instinctively shifted himself, accidentally giving the girl more access to the length beneath, which she was quickly growing increasingly interested in. The boy sighed in relief when he felt her hands lift from their placement, but he quickly realized why when he heard a zipper slowly lowering.

The boy tried to offer an out. “Kacchan, you don’t actually…”

“Shhhhh! Let me work!” But the girl wasn’t having it. Katsumi’s tenacity was something he typically admired from his best friend, but this was a little outside of the ordinary.

Izuku could feel her hands shaking as the zipper finally opened fully. She then performed a small maneuver to unlatch his belt and pants button. A moment of silence passed before Kasumi spoke up once more. “Raise your hips…”

Unsure of why, Izuku complied with the request but instantly regretted it when, in a sudden motion, Katsumi ripped down his pants and briefs, leaving his lower half nearly wholly bare. The girl's red eye bulged as she bore witness to the behemoth her friend was packing. Nine full inches of girthy dick was now seared into her brain for the rest of her life. “Holy shit Deku.”

Instinctively, Izuku went to cover his groin but was deflected by the small but deft hands of his companion. He wanted to complain, but before he could, one of those small hands found its way onto the boy's cock.

“Damn, dude. Fuckin’ big…” she whispered under her breath.

As much as Izuku was embarrassed, he was equally turned on. The girl who was objectively the most gorgeous in his class was now holding his dick in her hands. How could he not? The fight within him began to diminish, curiosity and arousal taking its place. Just how far would she go?

Izuku didn’t have to wait long to find out as he felt her hand grip his shaft and began to rub it back and forth awkwardly. The girl clearly had no idea what she was doing, but Izuku couldn’t deny that her growing enthusiasm was a major turn-on.

Conflicted on whether he should correct her on proper dick handling, the boy let her figure herself out, quickly remembering a fact about his childhood friend. She was a quick learner.

The motion of her hand rapidly grew smoother and more pleasurable for the man. Izuku couldn’t hold back a hum of approval as the girl grew more confident in her motion, something that only further drove the girl crazy. Internally, the girl was becoming addicted to this. This sensation of feeling the guy she had been not-so-secretly crushing on for years was squirming beneath her touch. It was intoxicating.

“You like that, huh?” Katsumi spoke for the first time in minutes. Voice hushed in a sultry tone Izuku didn’t know she could make. Izuku could only groan in response, eliciting the girl to continue her mission joyously. Humoring the girl, Izuku chose then to unbutton his shirt, revealing the muscled and toned body he had only recently acquired. At least for him. For Katsumi, however, it was the eye candy she had been salivating over for years. She bit her lip as she took stock and further amplified her motions.

Izuku’s cock flexed, straining and begging to burst under her ministrations. Suddenly, a new sensation joined the mix. A wet one. Izuku pried his eyes open to see a moist substance covering the girl's hand. A substance that smelled remarkably sweet.

His eyes burst wide open. “K-Kacchan is that-!”

The girl placed a finger on the boy's lips, hushing him as she continued to rub her sweat along his member. “Shh.. don’t worry.”

‘Easy for you to say…’ Izuku whined, realizing that the girl was using her nitroglycerin sweat as a lubricant for the handjob. Such worries quickly faded as the movement of her pumping hand accelerated from the decreased friction. Each movement bringing him closer and closer to the edge.

He desperately wanted to cum, mess be damned. He had to cum!

Izuku could feel his balls tighten, prepped and ready to burst, something Katsumi quickly caught onto. Returning to her sultry voice, the girl spoke up again, this time with a particular need in her voice. “Cum for me, Izuku. Do it.”

The uncommon use of his first name just about did it. The girl was pumping more furiously than ever, a certain desperation in its rhythm. Izuku himself couldn’t deny it anymore as his hips humped in the rhythm. It was time.

In an uncharacteristic roar, Izuku threw his head back against the bed and let loose the load Katsumi practically begged for. Streaks of cum shot forth from the boy's cock and just barely missed the blonde's face as they sprayed toward a conveniently placed stack of paper towels. His dick continued to flex as it was slowly milked and drained of all its contents, Katsumi’s hand continuing its motion in the meanwhile. Eventually, the impressive cock was utterly spent, twitching as the intense grip on it was finally released.

The boy sucked in the air, breathing for the first time in what felt like an eternity. “Holy… Kacchan, that was… Wow.”

Breathing heavily herself, Katsumi tried to **** off the silly grin on her face but failed. “W-Well don’t get used to it, Deku. This was just a-”

Katsumi Bakugo was cut off by a pair of lips crashing into her own as a pair of large hands wrapped around her fit waist. Tongues intertwined in a furious debate as the girl tried to rationalize the circumstance. Not only did she just give a handjob to her crush, but said crush was now making out with her! She could barely keep it together.

Seconds stretch into minutes as the two young adults continue their make-out session, time meaning nothing to them at this point. Izuku had long accepted that this was their life now. He may have accidentally made her like this, but he was damn sure going to see things through now.

Eventually, Izuku parted from his partner's lips, the girl nearly whimpering at the loss. “Kacchan… No... Katsumi.”

The girl bit her lip at the voice her crush was using. “W-what?”

Newfound confidence flooded the boy's veins as he watched the girl squirm in his arms. “I’ll take responsibility.”

The tomboy squeaked. “H-Huh!?”

The verdette breathed out and focused himself. “What I mean is… Will you be my girlfriend!”

Katsumi could die right there and still be the happiest girl in the world. That said, she was Katsumi Bakugo, the resident badass bitch. She wasn’t some doe-eyed school gi- “Okay…”

The words escaped before she could understand what she said. Izuku beamed at the response and kissed her again. “Awesome! I swear, I’ll make you the happiest in the world!”

Unfortunately, Katsumi couldn’t respond. Her consciousness slipped away with their second kiss.

After bringing Katsumi back to the land of consciousness and cleaning up their mess, the new couple returned to their classroom, none of their classmates aware of the circumstances that occurred in that nurse’s office. School continued as usual, except for the continued flirtatious glances Katsumi would send Izuku’s way from time to time.

Part of Izuku was absolutely over the moon about finally landing a girlfriend, though another part felt extremely guilty about the circumstances. Though Katsumi has no idea what he did to her and may never will, Izuku still felt immense guilt over his accidental edit of her life. Vowing to do better and not let something like this happen again, Izuku began jotting his observations in his trusty notebook.

New Quirk Observations:

• Activation Condition: Seems to activate based on strong emotional desires or thoughts.
• Range: Requires a personal connection or familiarity with the target.
• Effects: Alters reality, changing aspects of a person's life or physical state. Thoughts at the time of activation may be interpreted literally.
• Control: Limited understanding currently; changes seem permanent and resistant to reversal.

Examples:

• Mother: Altered to be fit and active, leading to a healthier lifestyle. Effects trickled down to me as our history was rewritten.
• All Might: Improved health with a healing quirk.
• Katsuki (now Katsumi): Gender change and altered personality/history.

Current Hypothesis: The quirk is potentially reality-warping, allowing for significant changes to people I know well. Requires further testing and control to understand limits and rules.

Izuku paused, tapping his pen against the notebook. 'This quirk is incredibly powerful and dangerous.’ A thought of those he changed flashed through his mind. ‘But… it also has so much potential to help people. I need to learn how to control it properly.’

Plan:

• Controlled Testing: Carefully test changing “minor” aspects with familiar individuals to gauge limits.
• Ethical Considerations: Always prioritize the well-being of others; avoid unnecessary risks. *IMPORTANT* No accidental changes!!!
• Training: Develop mental focus and control to direct the quirk more precisely. Find bare minimum for activation requirements.

With that written down, Izuku sighed in exhaustion. This wouldn’t be easy. Between getting ready for UA and figuring out this new quirk, life was going to get a hell of a lot more difficult.

But what is a hero's tale without a little bit of adversity?

**********

AN: Howdy Howdy! Here is the next installment of All Quirked Up. I hope y'all have been enjoying the story thus far. Today we get introduced to one of my favorite tropes in MHA fanfiction. Tomboy Katsumi Bakugo! God, I love writing about this type of character, so I hope you're excited to see more of her. As always, thank you all for reading and checking us out on my Discord for behind the scenes for all my writings. Lastly, a special thanks to Zephyr0F8 for beta-ing this chapter!