The Secret Life Of A Not-So-Useless Deku // A Vigilante Deku AU

Mister Muscle Is A Skeleton

Years passed, and Izuku entered his Iast year of middle school. lt was a shitty one, but Katsuki was with him, so he didn't complain. 

Any secret bullying done when Katsuki was away was dismissed by the teachers, who didn't care for a Quirkless kid with no future. They only cared about themselves, and with no gain from intervening, they turned a blind eye to it all.

Izuku managed to move out of his house at the start of the school year. It took a lot of fighting and blackmail until they finally cut ties, and lzuku was left on his own. He didn't mind anyway, with his information broker status that he had gained in the short span of a few months helped him with his money necessity. 

Now he was secretly gathering blackmail to help Katsuki out as well. Not many new, but the picture-perfect Katsuki actually had a tough home life. 

Mitsuki had quite the dislike for villains, having gone through a traumatic experience at the hand of one, and constantly shouted at Katsuki, who had an explosive temper (that he had gotten from her, which she had conveniently forgotten) for acting 'villainous'.

It got to the point where anything Katsuki did, she found a flaw, and screaming matches become more and more common occurances in the household. 

What Katsuki didn't know was that Izuku also knew about the physical part. Since young, vvhenever Katsuki had lost control of his Quirk, Mitsuki had slapped hirn, hard, until he stopped the explosions. It thankfully didn't escalate from there, but that was still abuse. 

Oh, and Masaru just stood by to watch it happen, the coward. 

So, Izuku dedicated hours everyday to finding dirt about the couple, even the smallest ones, and now, after three months of constant research, he had a file as thick as his thumb, more than enough blackmail. 

So, today Izuku was in a good mood, because he was finally going to confront the Bakugous about this. He was practically bouncing in excitement as the teacher shot him a glare, not that he cared. 

School was soon over and Izuku practically ran off to his house after telling Katsuki that he had an emergency to tend to. 

On his way home, he passed through a tunnel, and he was suddenly alerted by a foul smell entering his nose. He spun, hand grabbing the pen he was using to go over his plan once again in his notebook, and watched in morbid fascination as a slimy being appeared. 

The slime looked around anxiously, but as its eyes met Izuku's, a grin stretched on its disgusting looking face and he chuckled. 

"Ah, a perfect body to hide in. Don't worry kid,I just need to borrow your body. It will be over soon." As it made its way over to him, Izuku's mind worked overtime, analyzing for any weaknesses. Izuku found a few as he waited tensely, readying himself for what he was about to do.

As soon as it got close enough, in one fluid motion, lzuku stabbed the pen in its eye, and while it screamed, whipped out a half full water bottle from his bag. Quickly spraying the monster with the water and successfully diluting parts of it, he took a few steps back as it fell or the ground, the dilution making it harder to move.                                 

At that moment, a gust of wind flew by, and with a loud thud, an even louder noise rung out.

"FEAR NOT, FOR I AM HERE!" And All Might promptly gaped as he stared at the scene before him: a child standing across the villain he'd been chasing for the last twenty minutes, unharmed; and the villain on the ground, writhing in pain.

"Young man, d-did you do this?" he asked, internally horrified that a child could torture someone like that. Izuku just nodded, not oblivious to the hero's thoughts.

"I did, but it was all in self-defence. Plus, the only way to attack it would be its eyes, which are solid, and dilute the body, so what I did was necessary. I apologize for stealing your prey."

All Might was stumped. Calmly explaining hurting someone like that, what was with this child.

"May I have your name, my boy? I need it for the arrest records." Izuku sighed.

"Midoriya lzuku." All Might nodded, stuffing the villain into a plastic bottle.

"Then I must get going now, Young Midoriya." But just as he was going to jump, he felt something latch on his ankle, but couldn't stop himself as he took off. 

He looked down and saw the boy there. 

"Get off!" He cried out, which the boy scoffed at. 

"If I do that now, I'll die." As they landed on a rooftop, lzuku brushed himself off. 

"I apologise for the unpleasant surprise, but I have to ask you something." As he raised his head, he saw not All Might, but a sickly man with barely even muscle left. He blinked in shock. 

"Huh. A second form, huh. That makes quite a lot of sense. Nobody's ever seen All Might as a civilian before, after all." 

And All Might proceeded to tell him about the truth of his injury. Izuku hummed at the story, deep in thought. 

"I see. Well, I appreciate the story, but I have come to ask you a question,if I may?" 

All Might nodded. 

"Of course,my boy. What is it?" 

"Do you believe a Quirkless person can be a hero?" That struck a chord within All Might. He remembered the helplessness, the weakness he felt during the time he was Quirkless, and shook his head sadly at the boy. To think that someone would ask such a question.

"No, I don't. Someone with such a big disadvantage will only become a liability in the field." He looked at the boy one more time as he stood up. "Well then,I must get going now." 

He then took off, leaving a blank faced Izuku behind.

As soon as the man was gone, Izuku grinned.

He had just gained a good amount of blackmail on the No:1 Hero after all! 

Stopping the recording device in his pocket, he reached for the bottle of the slime villain in his other, shaking his head disappointedly. 

"How careless. Is this how the No:1 Hero should be?" He then jumped down the building, easily scaling the walls, and headed to the police station. It was a pity, but his plan for the Bakugous would have to be postponed.