Fire type quirks often affects the part of the personality mainly anger. Short fuse or a more potent expression of ones anger is something which unfortunatly happen quite often due to the common appearence of fire type quirk.
Blood or flesh quirks for example Vlad King and Moonfish respectivly have not a desire for blood or flesh but are forced to consume in order to get a resemblence of control. For quirks like these if you have the money or influance you can get from the hospital blood from tusted donors. For the ones who need flesh it is even harder. Not alone are the people looked at as villians they also have almost no way of getting what they need without breaking the law or someone to do or cover for them.
Izukus quirk is different then most seeing as it is semi sentient. In order to reawaken in Izuku it needed to be accepted. If the trauma would not have happened the greenhaired boy would have a different personality. The quirk of Izuku allows him in a permanent exchange of a good portion of his sanity or rationalism to get the ability to uses any fire arm and fire without reloading as long as he possesses enough stamina. The bigger the portion of sanity exchanged the stronger the firepower itself. Overuse of this causes a further lost of Sanity without the added boost of power though. The change was not only mental but also physical. The moment Izuku took the police officer gun in his hands his eyes went from green to a dark blue. The same change can be observed with his hair which went from green curly hair to a light blue straight hair. The lenth of his hair reaches now to the shoulderblades at the back. From the front ride side his hair is longer then on the left side. While on the left side his now straight hair frames his face the right side grows together a bit aweay from the face and reaches to the collarbone. The freckles on his faces dissapears as at the same time his skin tone became lighter making him very pale.
(This colour and style but without the twintails, the eyes are the same colour than jinx in the serie Arcade in the first few episodes.)
The quirk could only cause the awakening and changes due to Izuku not resisting it with believing that he is quirkless, seeing as his mind for many moments was completly empty after All Might crushed his dreams, it was finally succesfull in manifesting permamently. While the voices are all still there they also underwent a few changes. No longer do they have their grotesqe appearence but now they rather look like punk graffiti coming alive.
The officer notices nothing going around him as he was more focused on the various civilian trying to get closer to scene, so it doesnt register to him that the handgun on his hip was missing. The officer lookes around in hopes that the heroes are able to do something before the civilians get any closer and could be used as additional hostages by the villian. When looking around he notices the thin boy with blue hair next to him, his gun in the hand aimed at the villian with a manic smile. The officer could only look on shock at what was happening, unable to stop the teen in time for him to pull the trigger. A loud bang resonated through the street silencing everone but two people. The screams of pain from the villian and the insane laughter from the teenager brought a shudder down the spine of everyone in the vicinity. Before anyone could fully register what happened another shot rang through te air causing the people to recoil in shock and fear of beeing the one to be shot at this time. The shot to the relief of many hit the other eye of the villian causing him to let out another painfilled scream, further causing the teen to laugh stronger in delight. The pomerian who was held hostage just mere moments ago could not believe what happened. Many things went through his head, none of them more important to him than the fact that the useless nerd saved him. While arrogant Katsuki is anything but stupid. He realizes that he would have died if the nerd wouldnt have shot the villian, but that does not mean he will thank the useless nerd.
"TEXAS SMASH" shouted All MIght who suddenly appeart in front of the still screaming villian and punched the sludge villian yet again to cause him to splat on the various buildings. The punch was even powerful enough to cause rain helping put out the still on fire buildings.
After the villian was safely secured the police collected the two boys statement due to their involment in this case before beeing looked at by the ambulance that arrived to check the blond boy for any infestation or lingering sideeffects. All Might after his sudden appearence and heroic action was surroundet by horedes of fans and civilians. At the same time the heroes on place praised him for beeing brave in the face of danger and that he would be a great sidekick when he gets older. Seeing that the boy holds no respect for them he dismisses what they say.
On the other hand the former green haired, green haired boy is scolded by police and heroes alike for his reckless actions.
"Do you have any idea how dangerous and reckless that was? You could have caused even more problems for us."
"Yeah kid. I understands that kids your age want to become heroes but till your an official one leave the job to us proffesionals. We are after all trained and equipped to deal with these scenarios."
"Also what did you think your doing taking an officers firearm! You dont have a licence nor the allowence to use or hold a firearm. You ruin your record with shit like that, dont you know that? What you did was assault, illigal possession of an firearm, interfiering with a heroes and polices job and stealing from an officer. You are in big trouble mister. We are going to the station and are going to contact your guardian to inform them of this. YOur not getting out of this so easily."
While beeing lectured is nothing new for the teen, the awakening of his quirk caused several changes mentaly. The exchange of sanity and rationality for power allowes Izuku something he thinks he would have never done to no tarnisch his chances at a hero school. But now he doesnt think if it is a good or bad decision. He is going through with it.
"You were equipped and trained you say? Then why the fuck did you overcompensenting assholes just stand around crying that your quirks are useless here and you should wait for a hero with a better suited quirk? Kamui Woods could have thrown his branches at the villians eyes or backdraft, if he wouldnt have wasted energie and effort in putting out the fires which soon after where sent on fire again, could have dilluted the sludge making it difficult for the villian to keep an hold of the villian. Mount Lady had an excuse. WHile yes beeing new doesnt excuse incompentensie, she was unable to do anything because of the civilians blocking the way, which i hopefuly dont have to remind to should have cleared the way as soon as the police told them to retreat and make room for the heroes to work with. Without a quirk and only what was available to me from my surroundings i was able to do what you couldnt do. I saved a live. You stood there nothing as he could have died if the villian choked him any longer. You dipshits should either give up beeing heroes o go back to school because appearently the lesson of what it means to be a hero didnt reach you. Beeing a hero means risking ones own life in order to save someone without expecting glory, wealth, praise or reward in any form or shape."
Red faced in anger the heroes could only look as before they could stop him the boy walked off.
"Where do you think your going brat? We are not done here."
"We are done here. I am not wasting any more time on you shitheads. Im going home, go and clean up like the pathetic bitches you are!"
Stunned every one could not move. The newscrew, hoping to interwiew the victim or the boy who used the gun, had their cameras andmicrophone directed toward the pale boy making it very easy for the newscrew equippement to pick up the speech. As it was live through most parts of japan, many people heard awhat he had to say about the heroes which some agreed, or many disagreed with. Online discussion became very heated about what makes someone a hero and what the kid thought whar right he has to badmouth heroes.
As Death Arms tried to reach out and grab the kid, preventing him from escaping, Izuku starts running from the scene. As he was often chased by the bullies Izuku is well aware on where to run in order to make someone lose sight of him. With that Izuku escaped the heroes who are still trying to catch him and bring him to the police station.
When running Izuku never notices how All Might, still surrounded by journalists and civilians, gives him a sad smile. Blaming himself for causing the boy to snap and hate heroes is not something he thought he would ever cause. He wanted desperatly to run after the boy and apologize for what he said. All Might was moved that thwe same kid who asked him if someone quirkless could be a hero, was saving the hostage when the heroes on site had massive troubles. Seeing maybe a way to apologize and to find a successor the blond vows to himself to find the boy even if it takes a long time.
The boy in question already a good portion away from the chasers, stops to take a breather. The events of today running wild through his head. When he held the gun he felt a change happening yet he had no time to actually see for himself what that contains. Walking towards one of the parks near he walked to the fountain to look at the reflection to see if their are any optical changes. Lo and behold, Izuku was shocked at how he looks. His skin, hair and eyecolour changed drasticly. The shock also caused a revelation. As he doesnt recall beeing hit with a quirk he tries to recall the events to see what could be going on.
"I wasnt hit by someone quirk and nobody came forth when i was looked at by the paremedics so that possibility runs out. The students of Aldere also dont possess a quirk able to do this as the only one whos coming close let her change her eye and hair colour based on the emotion shes feeling. Could it be? No! The doctor said i had no quirk, that i have the toe joint. For fucks sake i still were the only shoes the quirkless could wear seeing as companies with the steady decrease of quirkless people startet to only produce the red obnoxias bright red shoes. So how?"
Deciding to think about it later the pale teen starts walking toward his home. Seeing how late it is he figures that his mother is home already from work. After half an hour he arrives at the door to his home. Taking out the key and opening the door all Izuku was greeted with was sight he never thought would happen. Most of the furnitur is gone as are all the picture and decoration in the house. Trying to find his mother proved futile as she doesnt seem to be home. There wee also no signs of forced entry. When looking through the rooms he notices something particular. The only place untouched was his own room. All the others had belongings taken but not his. As Izuku was till now an avid All Might fan his room looks more like an All Might shrine than a teenagers room. Poster and figurines everywhere. WHile Izuku would have smiled at the sight after today this only began to disgust him, but as there where more important matters right now he focuses on his search for answers. Trying to find a clue on what is going on Izuku stumbles upon a envelope sticking to the back of the door of his room so it could only be seeing if your inside. Checking the envelope so see whats going on causes him only further schock which quickly gave way to rage.
"Izuku
If your reading this im already gone. I couldnt just take it anymore. Since you were diagnozed quirkless everything i worked for so hard to archive was gone. My husband left because of you. I was fired multiple times from various jobs because of your status. I lost so many friends which only left me with Mitsuki and even that you managed to mess up. If you would have just toughend out Mitsuki and i would still be able to talk without problem. But because you couldnt do something as simple as that Mitsuki feels ashamed on how her son is treating you that she became distant, unable to look at me out of guilt and shame of not raising him better. Katsuki kun is perfect the way he is. He has a strong quirk which will give him many job opportunaties including becoming a hero. He is headstrong and knows what he wants whci are even archievable for him. While you could never become a hero without a quirk or get a decent job as nobody would hire you. You constantly destroyed my life and i had it with you. A few days ago i was called by Hisashi who wanted us to be together. Only me and him. The condition was to get rid of you or to move to him in amerika. As you can see all the things in the house belonging to me are gone as i took them with me. Because Hisashi, bless his kind heart, was able to be convince me that leaving the house to you would be a great farewell gift. The houses rent will be paid by Hisashi each month and a monthly allowance goes to your bank account. I couldnt care less if you live or die so never try to contact us. With this i washing my hands clean of you. Maybe when me and Hisashi try for another child they would not be such a dissapointed to us.
Farwell Inko"