Katsuki Bakagou's whole world was rocked on the day his Auntie Inko spanked him in his favorite park. He not only found out his favorite hero All Might had died in a fight with a super powerful villain but also discovered the his actions had consequences with the spanking. He also found out that he had been walking on a path towards being a villain and not a hero. That day he made vow to be better and asked his best friend Izuku to help him do that. So Izuku in his innocence suggested that perhaps Katsuki could be like Endeavor, a gruff but dependable protector of the innocent, someone villains would be afraid of. The only problem with that suggestion is it happened about ten minutes before the whole world found out how terrible of human Endeavor was. As the two boys watched the stream in horror Izuku whispered, "Kacchan, I don't think you should be like Endeavor anymore. We'll figure out how to make you a good hero in a different way ok?" Katsuki just nodded.
Seeing how angry Endeavor had been made Katsuki figure out he could get angry like that, so he decided that he had to not get angry like that anymore. He found it really hard because the more he held it in the harder it became to maintain. But he was going to be a great hero and no one would want to have anything to do with him if he was like Endeavor. But it turned out that trying to keep himself calm was a terrible idea because Katsuki started to feel weird and pass out, only to get pissed that he was being weak and then feel better afterwards which then turned into a cycle of anger and self loathing for him. Not knowing why this was happening and scared about becoming like Endeavor he turned to the smartest person he knew, Izuku.
Izuku thought about it and looked up information on medical conditions to try to help his best friend. That's when he discovered the medical use for nitroglycerin, which Katsuki's body produced as part of his quirk which meant his body was probably soaked in it consonantly which meant that his body had to have a way to counteract the effects of it. With this knowledge in hand Izuku dragged Katsuki to Mitsuki to have her help since she was Katsuki's mom. As Katsuki fidgeted beside his friend Izuku explained what the problem was and suggested that they should try to figure it out so Katsuki didn't hurt himself. With raised eyebrows and a breathy voice at the information dump Izuku had just laid on her Mitsuki told the boys that she will see about having a doctor runs some tests.
About a week later Mitsuki and the two boys are at the hospital to have the tests ran on Katsuki to find answers to the questions raised by the theory that Izuku had come up with. When the doctor asked what they were looking for Mitsuki pointed to Izuku to explain much to the doctor's surprise only for shock to overtake his features as Izuku laid out his theory and his fact backed reasoning behind it. With shaky hands the doctor just nodded and used his computer to start ordering tests for Katsuki. Soon the boy was in a room having blood drawn, then a CAT scan, followed by a MRI and other tests. By the time all the tests were done Katsuki was seething at being poked and prodded so much that he almost had steam coming from his ears, so Mitsuki decided that they would go get some lunch in the cafeteria to let her son calm down while they waited for the results and to also keep him from exploding the medical staff.
When they arrived at the cafeteria she saw Rei sitting with all her children, except her oldest Touya, eating lunch themselves. She walked over to check on her recently reacquired friend and ask about her missing son. As Rei tells Mitsuki that Touya was still healing but expected to be released in the next couple of days, Izuku studies the other three occupants of the table.
"Hello, I'm Izuku and this is Katsuki. It seems Auntie Mitsuki knows your mom, so I thought I'd introduce us since we might see each other in the future if they visit her home. If it's not rude can I asked what happened to your brother?" Izuku said as Mitsuki and Rei talked.
The three Himura children look at each other before Shoto slid out of his seat to stand in front of Izuku and Katsuki. "Our father beat him badly. I thought he was going to kill him. I'm glad some heros showed up to stop him." Shoto started to cry as he explained which caused Izuku to lunge forward to hug the boy before anyone else could react as he repeatedly said "I'm sorry for asking."
Katsuki looked on as he thought about the boy's story before it clicked in his mind and he could barely kept from exploding as he ground out through grit teeth, "Oh your father is that flaming shit pile Endeavor isn't he. I hope he gets what's coming to him. Though I'd really like to explode him in the face." His hands started to pop with explosions and his body suddenly felt better making him stand straighter. Everyone watched as the blonde boy went from being slightly off color to a healthy glow in less then a minute. Izuku tilted his head as he studied his friend's transformation before his eyes while he comforted Shoto. Meanwhile Fuyumi and Natsuo both slipped out of their seats to take their brother into their arms once they indicated to Izuku that they would take Shoto from him. Izuku moved towards his friend as the boy stood there getting worked up on the behalf of the Himura family, noticing that Katsuki looked remarkably better the angrier he got. Mitsuki also noticed that her son was healthier looking as she watched the scene in front of her. Before anything else could happen her phone rang and when she answered she was informed the doctor had the results back already and would like them to come back to talk to him.
After saying goodbye to the Himura family, Mitsuki and the boys hurried back to the doctor's office to receive the results to Katsuki's tests. When they arrived back the doctor commented on how Katsuki looked much improved to which Mitsuki explained that he had gotten angry and seemed to come to life in front of them. The doctor nodded at this information before he told them that was in line with what they had discovered in the tests. He went on to tell them that Izuku had been correct that Katsuki's body was constantly producing nitroglycerin and they found larger and more active adrenal glands throughout his body that seemed to work to counteract the effects of the nitroglycerin. They also found that his brain was wired slightly different in that it seemed more prone to making him boisterous and hyped up to activate the adrenal system. The doctor said it probably came out right now mostly as anger at his age because he didn't know how to channel it effectively. He suggested setting Katsuki up with a therapist to help him not so much to manage his anger and other emotions as so much as learn to channel it in a healthy way. Mitsuki thanked the doctor and took the information for a well reviewed therapist he suggested as she stood to leave while herding the boys out of the office.
Several weeks later Katsuki had met with the therapist and had already started improving once she assured him that just because his quirk had the side effect of making him aggressive didn't mean he was going to turn out like Endeavor. She told him in fact that if he could learn to channel his aggressiveness in the correct way that it could lead to him being seen as a no nonsense type of hero in future who struck fast and strong to protect citizens. Katsuki took those words to heart and vowed to be best hero he could be.
Another thing to happen was Izuku and Katsuki went from being a duo to a trio. Soon after the visit to the hospital Rei Himura visited the Bakagou house with her children while Izuku and Inko were there to reacquaint herself with her past friends. Inko and Mitsuki quickly embraced their friend and fell into getting to know each other again. Touya, Fuyumi and Natsuo all followed their mother as the three women visited while Shoto hung back because the mothers had started to get louder as they told stories about each other from their youth. He still associated loud voices with the yelling his father had done when training (beating) him so he was nervous. So when a green headed ball of energy popped up beside him he felt he was not to blame for reacting by freezing the boy's feet to the floor while jumping back in a battle stance. Expecting the boy to be angry that he had attacked him, he was not prepared for the boy to look at him with stars in his eyes before the blonde boy that seemed to hate his father, which put him in Shoto's good graces, casually leaned down to break his ice with a small explosion releasing the green haired boy. "You showed him your quirk so you're in for it now. Sorry." the blonde said as he stepped back.
The green haired boy practically teleported across the room to Shoto's side, "Hello again. I'm Izuku. Nice to meet you again. Your quirk is so cool. Is it just ice? Or is it fire too? Is that why your hair is two toned? If you can use both then you should be able to regulate your temperature unlike Endeavor, asshole that he is. Oh shit I need to quit listening to Katsuki, my mom would wash my mouth out if she heard me. Anyway you have an awesome quirk. Are you going to be a hero? It would be great for that. I can help you out if you want just like I'm helping Katsuki with his so he can be a hero. I bet it would really piss off your dad if you became a hero in spite of him. You could be a much better hero then him since you would be able to keep yourself from overheating like him. Plus you could flip from using flames to ice depending on the situation making you more versatile being able to do combat and rescue work. What do you think?" Izuku said, talking almost too fast to follow, causing Shoto's eyes to widen and his eyebrows to rises in alarm. Tilting his head like a adorable puppy Izuku asked what was wrong which caused Katsuki to laugh and step forward.
"Zuku, you probably just scared the shit out of him. You just talked so fast that it was almost a hum of words. I know your brain works fast but you have to let the rest of us catch up sometimes." Turning to Shoto he continued speaking, "Sorry for turning him loose on you but I thought you deserved it for freezing his feet earlier. Besides it was funny watching you get more and more confused as he talked." Beside him Izuku made a small hurt noise he had scared a new friend.
Shoto stared at the two boys as he calmed down from the verbal assault from Izuku and thought through what the green haired boy had said. "Uh, yes I can use fire and ice. My fath- um, Endeavor only focused on training me and Touya in using our quirks to fight. I don't know if I want to be a hero. It has always been something that was expected of me, not something I had a choice in. I know Fuyumi wanted to be a hero with her ice but Endeavor just dismissed her out of hand. Maybe you could help her? I have to think about what I want. But thank you." As the two toned haired boy looked at the other two boys he saw that Izuku had a thoughtful look on his face while Katsuki look slightly insulted.
"You have an awesome quirk like that and you don't want to be a hero? I feel like I should smack you just for general purpose. What the hell!?" Katsuki started to rant only to be stopped as Izuku put his hand on his arm stopping him before he got going too strongly. Looking at his friend Katsuki saw the slight shake of the other boy's head. He huffed out a breath as he swallowed his rant as Izuku took a step forward.
Placing his hands on Shoto's shoulders, slightly startling the boy, he looked him in the eyes. "Whether you want to be a hero or not is your choice. If you felt I or Katsuki were pressuring you then I am sorry. It has been him and mine's dream to be heros since we were old enough to know what heros were. While Katsuki developed a great quirk, I was diagnosed as quirkless. So recently my dream has changed from being a hero to helping him become the best hero he can be. When All Might died I realized that fighting alone is what got him killed and after looking into information on the internet I found most hero deaths are the result of them trying to go it alone and refusing to work with other heros, mostly because they don't want to possibly be overshadowed in the press. So I want to find teammates to fight along side him. People to support and complement him in the future. I think you could be a good match and a force to be reckoned with your quirk. But that is your decision, not something that I would force on you. I know I got excited by your quirk earlier but you have to admit your quirk is awesome."
Shoto blinked at the speech Izuku said to him as the boy kept eye contact to let him know he meant every word. His mind raced as someone told him it was his choice to be a hero for the first time. He rapidly thought about it, thought how he could be the hero he wanted to be, not the one his father wanted him to be. As Izuku released his shoulders and stepped back next to Katsuki, they all were startled to hear someone clear their throat.
As the three boys looked over they saw Touya leaning against the doorjamb with Natsuo peeking around him. "We got bored listening to the moms visit so we thought we would see what you were up to. Couldn't help hear the greenbean talking. He is right you know, being a hero is your choice, not anyone else's. Even though I been through so much because of our crapstain of a father, I still want to be a hero. I want to make sure no one ever has to live through what we have and punish anyone to acting like the flaming dumpster fire like our dad is. Or at least as long as I can since my quirk hurts me eventually while using it."
Almost immediately Izuku was in front of Touya looking up at the older boy. "Your quirk hurts you? Don't you have support gear to help with that? Also what is your quirk?"
Stepping back after the young boy appeared in front of him Touya answered quickly without thinking. "I call it Cremation, I produce blue flames that are hotter then even Endeavor's flames. But I also have a body suited to an ice quirk user like mom. As for support gear I've never had any. Our asshole father didn't believe in it as he saw it as a crutch for a hero." He ended with a dark look on his face.
"Well fuck that. That asshole doesn't get to dictate shit like that anymore right? That douchebag is rotting in jail for what he did to you all. Why would you keep following what he said?" Katsuki spouted out as Izuku softly mumbled in front of Touya, what Katsuki said making the older boy's eyes widen in realization at what he had been doing concerning his quirk.
Izuku came back to the world from wherever he had been inside his mind as he spoke, "Have you been trying to use your flames like Endeavor, full on, all the time?" At Touya's nod he continued, "If you have good control of your quirk you should learn to fight hand to hand and use short bursts of flames to damage your opponent. Also figure out or have someone design you gloves and sleeves of fire proof material to protect your skin. If you limit the time you have your quirk on you shouldn't burn your skin as easily and probably increase the time you can fight because you wouldn't lose your stamina as quickly by trying to keep it on as much and dealing with the pain of being burnt. Maybe also look into burn resistant gel. I saw a documentary once about stuntmen that showed them having to do a stunt that involved having to be on fire and they spread it on their exposed skin to protect it from the flames and heat."
Touya absorbed everything Izuku told him as the young boy revealed a completely new way to use his quirk to be a hero. After how Katsuki and Izuku had made him realize he had still been letting his father dictate how he used his quirk, the older boy wandered back towards where his mother was still talking with her friends. As he sat down on the sofa with a dazed look on his face Mitsuki took notice of the look on his face.
"You talked to Izuku about your quirk didn't you? Completely rearranged your outlook on it didn't he? I had the same look on my face a few weeks ago when he came to me with my brat in tow to tell me I needed to have him checked out to find out why his quirk was effecting him so negatively when he was trying to not act like the second coming of Endeavor by being angry all the time. I don't think the kid realizes he is so much smarter then everyone else that he regularly rocks people's worlds so easily. Just take your time to process what he said and watch yourself in the future when you talk to him again so he doesn't blow up your world view again." The blonde mother said as Rei looked on in concern for her son while Inko smirked with pride at hearing other people realizing how smart her son was.
Meanwhile back with the other boys Izuku looked back at the other boys with panic on his face. "Did I say something wrong? I was only trying to help."
Natsuo spoke up from the side, "I think you broke him a little bit. No one has ever tried to suggest a different way to use his quirk. Only how our sperm donor has shown him how to use it is the way he has ever used it. I think it was so ingrained in his mind that he didn't realize he was still letting Endeavor dictate to him how to use his quirk. Personally I don't want to be a hero. Watching the dickhead spoiled the appeal for me. I want to be a doctor so my ice quirk wouldn't be very useful for that, so I wouldn't need to train it for that."
Izuku spun around instantly, "Actually your quirk could be very useful in that profession. Operating rooms are usually kept at low temperatures during surgery to put less stress on the patient. Also you could lower a person's body temperature in an emergency to slow blood loss or combat shock due to limb loss. Or help fight a fever in a person due to illness. If you could control it well enough you could even make emergency tools of ice that would be sterile and free from infection at an accident site if you were on scene of a rescue." what the young boy said shocking the slightly older boy as he rattled off uses of his quirk in the medical field. Katsuki just shook his head as Izuku blew the lid off another person's mind.
"I think that's enough for today Zuku. You scrambled the minds of those two enough ok?" he told the green haired boy as he put his arm around his shoulders so he could lead him away from Natsuo as the boy looked at his hand as he brought up his ice as he tried to concentrate to make it form into the shape he wanted. As a crude small knife formed in his hand the boy started walking away towards the mothers.
Shoto watched everything that happened as Izuku turned both of his brother's world view of their quirks on it's head. He thought about how he had been excited at first when his father had said he was going to train him to be a hero when he was younger. But then the training turned out to be an excuse to beat him and Touya so they would 'toughen up' to be able to be Endeavor's perfect little soldiers under his thumb. He still wanted to be a hero deep down but he didn't want be one like his father, with no care for everyone else, just focused on gaining more power and fame. He wanted to help people, be a great hero like All Might had been. As he looked at Izuku and Katsuki he thought about what Izuku had said about working together as team to be better heros, to not go it alone when facing a challenge. To build each other up instead of trying to tear each other down in the pursuit of glory and power. The more he thought it, the more he felt the dying embers of his desire to be a hero that Endeavor had been slowly killing, come back to life as he realized he could be the hero he wanted to be instead of the one his father wanted him to be.
Shoto cleared his throat to get the attention of the two boys before he spoke the words that would bond him to the other two for life, "I want to be a hero. I want to be a better hero then my father. Please help me do that." Katsuki slapped him on the back as he laughed while Izuku smiled so brightly that Shoto wished he had sunglasses for his eyes.
After that day the three boys were inseparable. As the trial of Endeavor went forward Izuku and Katsuki were there by Shoto's side to help him deal with everything. When he had to give a video deposition with a court reporter and an impartial advocate about what Endeavor had done to him he asked if they could be nearby for moral support. Afterwards Izuku hugged him and consoled him while Katsuki raged in his defense while keeping everyone away to let him collect himself. He thought it was nice to have people to lean on and support him when he couldn't be strong.
The three of them watched as Inko destroyed Endeavor in court as she dragged every dirty secret Endeavor had into the light of day as well as take down some corrupt officials of the HPSC that helped cover up Endeavor's crimes and home life. She also sued the Himura family on behalf of Rei for selling her into the life they did and forcing her into a quirk marriage. By the end of everything in the courts Rei owned everything of Endeavor's and got a huge settlement from her family with provisions that they were to have no contact with her or her children. All in all Inko raked them all over the coals in her pursuit of justice.
Rei ended up selling the huge mansion they had lived in because it had too many bad memories and she felt they all needed a fresh start. She bought a large house near the Midoriyas and Bakugous to be near her friends and so Shoto could be with his new friends too. They all soon fell into a new routine of life as all the families intermingled to form a small village like atmosphere that supported all the children in the families. When Touya decided to take marital art lessons due to Izuku's advice on how to use his quirk, all the parents decided to see if the rest of the children would want to do so too. To no one's surprise Katsuki immediately wanted to as well as Izuku who wanted to be able to defend himself from attacks for being quirkless. Shoto also joined once Izuku told him it would be good to learn to fight hand to hand if he was somewhere it would be dangerous to use his quirk such as if a villain broke a gas line to stop him from using his fire or perhaps set off a fire sprinkler to stop his flames and his ice since it would freeze the water and possibly endanger a building or hostages. No, the surprise came due to the fact Natsuo and Fuyumi both wanted to learn to defend themselves so that no one could hurt them again without consequences.
Another surprise that happened was when they started enquiring about dojos for the children they were approached by the representative of a master who wished to train the children. So they all decided to check out the person that wanted to teach their children and already knew of them. Which made them weary that this would be some kind of revenge plot since it was well known that they were all part of the reason for the downfall of the number two hero so soon after the death of the number one hero.
When they arrive at what looked like a recently renovated building all of them were very cautious entering the building, Inko keeping a hovering finger over the number of Detective Tsukauchi in case this was a trap. They all approached a figure that seemed to be meditating in the middle of the floor on a cushion. As they got near the figure looked up at them to reveal an old rat man. Their surprise at the appearance of the man was only seconded by the strength of the shout from Izuku of, "Master Splinter!"