Inside the teacher's lounge, Yagi Toshinori was being chewed out over the phone by his mentor, Gran Torino.
"Toshinori, you fool! At first I thought you chose that boy because you saw potential in him, turns out you only saw your foolish, reckless younger self!" Gran Torino's voice roared through the receiver.
Toshinori had taken Midoriya under his wing to train him in controlling One for All. But the boy… hadn't been doing well. He could lower the output of the Quirk, sure, but beyond that, he was distracted, unfocused, his mind constantly wandering elsewhere. Progress was painfully slow.
And then came the patrol incident. When the Nomu attacked the train, Torino ordered Midoriya to stay behind and protect the civilians while he handled the creature. Instead, the boy bolted without hesitation. The civilians were unharmed, by sheer luck, but Midoriya's brilliant idea was to go looking for the Hero Killer.
If Decade hadn't been there, Midoriya could've died that night.
Torino also knew about Tsutsumi. The boy had spent most of his life believing his Quirk was worthless, living like someone quirkless. Then, the moment he understood its true nature, he mastered it and picked up countless skills in barely a year, something that should've taken years, maybe decades.
Worse still, Tsutsumi was right there, attending U.A. and living close to Musutafu. Toshinori could have crossed paths with him easily, or simply waited for the entrance exams before choosing his successor.
That thought gnawed at everyone who knew the truth of One for All. Nezu, Toshinori, Torino, even Midoriya himself, they all wondered the same thing: if Tsutsumi had inherited One for All, just how long would it take him to master it?
The Sports Festival only deepened the question. In the finals against Bakugo, Tsutsumi didn't even use his own power, he fought with the Quirks of his classmates, proving not just what he could do, but how much more they could improve.
The more Gran Torino dwelled on it, the harsher his words became, hammering Toshinori with every regret and possibility.
Finally, after what felt like hours, Torino's tone dropped. His voice grew cold."Toshinori… those Nomu you fought. I have a suspicion they were created by him. Your old nemesis. The man who can steal Quirks."
There was a pause heavy enough to crush the air between them.
"All For One."
...
Meanwhile, back in Classroom 1-A.
"Heh?" Tsutsumi blinked at the thick stack of papers dropped onto his desk. "What's this supposed to be?"
He looked up to see Aizawa standing over him, looking as tired as ever.
"Documents about your classmates. Addresses, birthdays, hobbies, Quirks, and so on," Aizawa explained in his usual monotone. "You've shown great mastery over your classmates' Quirks. I want you to design training regimens for them. After all, 1-A has already been targeted by villains. Better preparation is necessary."
Tsutsumi gave him a flat, deadpan stare. "You just want to dump your job on me so you can sleep, don't you?"
"Somewhat," Aizawa replied without hesitation, cutting straight to the point. "Many of your classmates still struggle with their Quirks. Some don't even have proper fighting styles. With your knowledge, helping them should be easy."
His gaze drifted toward Bakugo. "Even Bakugo's Quirk, you managed to refine it and pull a move beyond what he could achieve himself."
Around the room, the rest of the class perked up, staring at Tsutsumi with expectant eyes.
"Don't wanna." Tsutsumi leaned back in his chair, ignoring the disappointed sighs from his peers. "I didn't sign up for this position, so you can't force me."
"I see." Aizawa didn't even flinch. He knew how to handle this kid. "Then who would you be willing to help?"
Aizawa understood Tsutsumi well enough. The boy wasn't going to lift a finger for people he disliked; Midoriya, Mineta, and Ida could forget about it. But if someone like Jiro asked. He'd probably say yes after doing something to annoy her.
People helped those they were close to, not the ones they couldn't stand.
"You really are a lazy teacher," Tsutsumi muttered, scribbling on the papers anyway. He handed back a short list: Jiro, Bakugo, Todoroki, Tokoyami, Kirishima, Shoji, Kaminari… and Aizawa.
The last name made Aizawa blink. His brow creased. "…Me? What could you possibly help me improve?"
"You know how to use your Quirk," Tsutsumi said calmly, reclining in his chair. "But you don't know how to use it efficiently."
Aizawa's eyes narrowed, intrigued despite himself. "I see. Can you demonstrate?"
...
At one of U.A.'s training grounds, Aizawa gathered the entire class to watch as Tsutsumi demonstrated how he could "improve" on Aizawa's Quirk.
"So," Tsutsumi spread his arms wide, confident as ever. "Who wants to be my test subject?"
"Me!"
Bakugo and Todoroki spoke at the exact same time. Both froze, then slowly turned toward each other.
They had both lost to Tsutsumi before, both had received his guidance, both had grown stronger because of it. And now, both wanted to measure their progress against him.
The air between them sparked as their glares clashed, neither willing to back down.
"Alright then," Tsutsumi smirked, "how about you both come at me?"
That drew their attention back. They stared at him, eyes burning with determination.
Bakugo pulled his hand close to his chest, fist clenching tight. "I'll let my passion burn and crush you!"
Todoroki calmly spread his arms out. "You're going to be a sacrifice for the greater good."
The entire class blinked, taken aback. Those lines… were actually kind of cool.
It wasn't random either. The two had spent long nights training, remembering how Tsutsumi always had a sharp catchphrase. Inspired, they'd started experimenting with their own. After all, All Might had "I am here!" a symbol of hope wrapped in a single phrase.
And now, their rival wasn't just ahead in power, but in presence, in style. They refused to be left behind. Their catchphrases were the first step in closing that gap.
Tsutsumi ran a hand through his hair, slicking it back with a grin. "Then come."
Attack Ride: Erasure!
Bakugo blasted forward first, explosions propelling him straight at Tsutsumi.
The purple-haired teen narrowed his gaze, Bakugo's quirk cut off instantly, dropping him out of the air and sending him tumbling across the ground.
Tsutsumi spun on his heel, a sharp kick snapping toward the blonde. Bakugo crossed his arms to block, bracing for impact, only for a wave of ice to surge at him from behind. It froze mid-rush as Tsutsumi redirected his gaze. Bakugo scrambled upright just as a right hook came his way, forcing him back again.
Todoroki pressed the attack, sending another blast of ice. Tsutsumi vaulted over it, landing lightly atop the frozen trail before canceling it outright. He dashed forward, closing the distance.
Behind him, Bakugo roared and launched another explosion, only for it to sputter out mid-air. He almost face-planted before catching himself on the ice.
Todoroki raised his arm in defense as Tsutsumi's kick slammed into him, the blow sending him sliding backward. Tsutsumi pressed in, forcing Todoroki into close combat. Punches and counters flew, but the dual-haired boy was clearly on the back foot.
"You rely too much on your quirk," Tsutsumi said coldly, slipping under a strike before slamming an uppercut into Todoroki's chin. The blow lifted him off his feet.
Tsutsumi didn't even pause; he pivoted just as Bakugo's explosion fizzled out, and drove a fist straight into the blonde's gut.
Bakugo staggered, but came back swinging. Sparks cracked as the two exchanged rapid blows, fists, knees, kicks, until Todoroki rejoined, launching a kick of his own. Tsutsumi blocked it without looking, caught between both of them.
The fight shifted into pure physical combat. Bakugo and Todoroki fought with brute strength and raw instinct, while Tsutsumi toyed with them, pushing both to their limits.
"Todoroki, move your hips while you punch; it will add more force."
"Bakugo, calm down, anger only clouds your judgment."
"Todoroki, I suggest you study another form of combat. Without your quirk, you're quite weak."
"Bakugo, stop screaming, you don't want the enemy to throw dirt into your mouth during the fight now, would you?"
The class watching from the sidelines couldn't believe their ears. Was this a spar or a live critique session?
The clash peaked when Tsutsumi caught both their punches at once, gripping their fists with iron strength. In the same heartbeat, both boys threw their free hands forward, smashing into his chest and finally shoving him back a few steps.
"That's enough." Aizawa finally cut in, satisfied that Tsutsumi had used the spar to hone Bakugo and Todoroki's weak points.
He turned his tired gaze to the purple-haired kid. "So, what did you want to show me about my quirk?"
"I…stopped using it a while ago." Tsutsumi said, flat. The admission landed like a punch, Bakugo and Todoroki blinked, and even Aizawa's expression tightened.
"Erasure only needs a line of sight to the target," Tsutsumi continued, voice calm as ever. "By switching it on and off in the middle of a fight, I make the opponent misread their own situation."
He looked at the two boys, eyes cool. "Bakugo, after having his shut off mid-use and getting hit a few times, stop relying on his. Todoroki learned the same way, failed to make a barrier or avoid, got hit, and started relying on his body instead. The human body learns to avoid the things that hurt it. After the first fall, you guard against it. Same with a quirk: after it fails and you get punched in the face enough, your body will automatically try to move without using the quirk."
Aizawa murmured, thoughtful. "Interesting. In a long fight, that kind of wear-and-tear adds up."
Tsutsumi flicked his hair down. "Also, when you use your quirk, your hair spikes. Not many notice, but if someone does, you can slick it back with gel. Makes it harder to tell when you're about to activate."
Aizawa's tired face softened into a rare nod. The hair-gel tip was borderline trivial, but practical. In high-stakes fights, a single second's surprise could be the difference between life and death. Tsutsumi's whole approach was disruption: make the enemy doubt their quirk, force them to fight with their body, and exploit the hesitation.
The teacher allowed himself a small, satisfied smile. The Problem Child, annoying as he was, had actually done something useful.
"While you're at it," Aizawa said, pragmatic, "help the others you can. Nezu's willing to overlook some absences if you do."
Tsutsumi rolled his eyes. "I don't get paid enough for this."
"Then pick who you want to help," Aizawa said bluntly. He knew Tsutsumi wouldn't do favors indiscriminately, only the ones he cared about or thought worth the effort.
Tsutsumi scanned the class, tossed a lazy smirk, and called out, "Kirishima. Kaminari. Step up. Aizawa-sensei just told me I can break all your bones."
Everyone: "..."
The day slipped by quickly as Tsutsumi moved from one classmate to another, guiding them through the basics. The basics were all the same; they must at least know how to fight without their quirk first, even if they can master their quirk, it would all fail if they suddenly found themselves defenseless when unable to use their quirk.
Kaminari and Shoji were thrown into endurance training, each for different reasons. Shoji had solid control, but he is a bit of a whim, so the endurance training is to toughen him up. Kaminari, on the other hand, still couldn't handle his own Quirk without short-circuiting. If he couldn't control it yet, then at least he had to learn to withstand the backlash without turning useless.
Tokoyami's control was decent, but he still lacked acceptance and control, so Tsutsumi just made him train in a dark room, causing Dark Shadow to act defiantly, then made him stay in that room and learn to control it. Once he gains control over it, Tsutsumi would send him into an even darker room and continue the training.
Bakugo and Todoroki focus on strengthening their body and honing their combat skills that don't rely on their Quirk all the time. For fighters like them, raw skill would decide whether they stood above or fell short.
Meanwhile, Jiro kept up her own regimen while helping the other girls. Her methods, however, weren't exactly gentle, more than a few classmates had already taken a kick to the face before being ordered to get up and keep going.