Ever since you were a child, you were never the one who started a fight, but you were always the one who ended them.
Being orphaned at a young age due to the looming war, you only ever had your older sister and your little brother. War had taught you a lot of things at a very young age.
How to steal, how to make do with one meal a day, how to ignore the stench of rotting corpses, how to raise your brother while your sister was away looking for food and shelter and most importantly, how to use your quirk.
Quirks were a relatively newer ability that humans had begun to develop. About 50% of the population had them, while the rest of the 50% was still quirkless, normal humans. Neither of your parents had a quirk, as far as you could remember, so obviously you didn't expect to get one either.
Not to mention, your sister was quirkless too. So you had expected the same fate. But sooner than later, you had found out that you were different.
You did have a quirk; Temperature Control.
You could control the temperature of anything and everything. You could control the temperature of the air, the bodies of humans, food, anything.
At first, you would use it to warm your siblings when the nights were too cold and you three scampered together in the dingy little hut that you called home. Your brother was a growing child and as were you, so your sister began to work even harder to get food for you three.
But she made you promise something very important. To never reveal your quirk infront of the military officials. With the war being as rampant as ever, the government had been trying to get as many quirk-wielding soldiers as they could. She didn't want you to be drafted in the army and neither did you want to be taken away. You may not have a lot to eat, have dirty clothes, dirt and grim coating your skins, murky water to drink, and no roof on top of your heads, but you were happy with your family.
So you promised her and stuck to it.
But, life was never fair to anyone.
The temporary illusion of peace that you shared with your siblings was soon shattered when another strike of war raged at the outskirts of where your sister worked.
She had left for work one day... and never came back.
And thus, at the age of ten, you were the eldest sibling left in order to raise your 4 year old brother. With how the area had been close to getting ingulfed in the flames of the ongoing war, you decided to relocate yourself and your brother to a small town that was still relatively safer than the rest of Japan.
Life there was simple.
You got up. You made breakfast for yourself and your brother, you'd chop wood and sell it at the town before going fishing to make lunch. After that, you would sell the extra caught fish at the town before finally going back home to your brother.
It wasn't a bad life.
Sure, your heart ached at the loss of your sister and you wished for revenge, but what could a weak girl like you do? So ultimately, you extinguished the fire of vengeance in your heart to raise your brother.
One day, you were out fishing like usual when you came across something that was bubbling in the river. You peered inside to see... A person, a boy. In a heartbeat, you jumped inside and immediately pulled him out.
He had pretty, short white hair, spotless pale skin and soft pink eyes that glowed a gorgeous magenta color when light shined upon them. He seemed to be around the same age as you.
The moment you pulled him out, he took a gasping breath of air before lying in shock at how he was still alive, "Oh... oh, I..." He couldn't even form words, coughs rattling through his weaker form.
You weren't the strongest person around, but at least you had some muscle. But this guy looked like a pile of bones and skin. Noticing his shivering state, you carefully slid over before wrapping an arm around him and activating your quirk. You could have done it without touching but you figured that he would have been freaked out if he was suddenly warm without any source of heat.
"W-Wha..." He stammered, burning a bright red color upon seeing you giving him a half hug, "Are you okay?" He didn't trust his voice enough to answer you, so he simply nodded fervently.
Bestowing him a saccharine smile, you softly started, "I see, I'm glad. What even happened to you?" The boy's blush died down and a pitiful look overtook his features, "Bullies... They tried to drown me... because they knew I couldn't swim..."
You felt anger pulsing through your veins. How dare someone try to take a person's life?! Who the fuck gave them the right to drown someone?!
"It's okay... I'll protect you, don't worry!" He lowered his head, tears slowly pooling in his eyes at your words.
He had never felt such kindess from anyone in his life.
"My name is [Last Name][Name]! What about you?" He gave you a shake smile before speaking.
"Nozomi... Just Nozomi."
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Ever since that day, Nozomi had began to live with you and your brother. You were quick to find out that he was also an orphan whose parents had left him at the town's orphanage. It was why he was bullied; because according to the other kids, he was an unwanted person that not even his parents wanted.
"You're not unwanted. You deserve to be here just as much as anyone else..." You would say to him whenever he apologized for being a burden. On top of being an orphan, he had a very weak body. He would get sick easily and he couldn't lift a log of wood, even if he tried.
But regardless of all that, he was someone special to you and your brother. In fact, you're sure your brother loved Nozomi more than he loved you.
And by the time you had turned 12, you would feel your heart racing everytime you saw Nozomi. And by the time you had turned 13, you had begun dating him. He was a sweetheart, always trying his best in everything he did, even if he knew he wasn't good at something. He just wanted to help you just like you had helped him.
Yet, you were reminded once more of how unfair life was. Because the war that you and your brother had so narrowly escaped, was now knocking at your door.
Apparently, the soldiers in the army were beginning to dwindle in number and with no other resort, the government had begun sending officials to every town to draft people. There were only two options for the picking of soldiers, either you were a man, or you had a quirk.
From each household, at least one person was required to be drafted, be it man or woman (if she had a quirk). And things finally took a turn for the worst, when your family was subjected for being drafted. If you didn't step up, they would have either drafted Nozomi, or [Brother Name].
And you wanted nothing more than to keep them both as far away from the war, as you could.
So you broke your promise to your sister and ultimately revealed your quirk. The officials rejoiced upon finding out that you not only had a quirk, but it was one that could be extremely powerful if trained properly.
Being drafted in the army wasn't the worst thing.
Sure, you had to wake up extremely early, train from morning till evening and work your ass off if you didn't want to get punched by the instructor.
But there was warm food to eat, soft beds to sleep in, clean clothes and pure water to drink and bathe in.
So maybe, it wasn't that bad.
Not to mention, they even gave you all pays to send back to your families. And you were glad to say that it was enough for your brother and Nozomi to live comfortably.
You worked day and night to train your quirk, and your body. Every weapon that had ever been invented was taught to you, so you could expertly wield it. You grew stronger and stronger as more time went by.
But the real horror began after you had finished your training.
Horrors of war struck all over the country and even throughout the world. Blood was spilled, lives were lost, families were torn apart and houses were destroyed.
All because of that one being, All For One.
You knew that there was someone out there who was meant to fight him, someone meant to take him on. But that person was nowhere to be found, the government told you he was training in hiding.
But you didn't care about that. All you saw was how much of a coward he was, how he refused to take responsibility for a battle that was essentially his fight.
Why did you have to lose your friends and superiors to a war that was never meant to be yours?
Hatred, it was all you had felt.
Hatred, it was what fueled you into surviving.
You swore to yourself, that you would build a peaceful world for both your brother and Nozomi.
They were all you had, they were your everything.
And you'll be damned if you let anything ruin their lives.
Your quirk, the more you trained it, the stronger it got. You grew stronger and stronger, facing more and more of All For One's subordinates.
They all wanted one thing, destruction.
You were always a pacifist. After losing your loved ones, you didn't find it in you to hurt anyone and make them go through the same grief as you did.
But at this moment, you didn't care. You wanted these scums of society gone. Your rage kept building up, your quirk slowly but surely getting stronger.
And in the blink of an eye, the bodies of every single one of your enemies were now burning to the ground, scorching in the heat. You learned later on that it was your doing; you had raised the temperatures of the air around everyone but you, to such an extent that it was practically an oven.
That one battle changed everything.
You were renowned as Phlegethon, the soldier who could take down an entire brigade if she wished to. You did not like how the government paraded you, how they treated you as their weapon.
But if it meant building a more peaceful world for your loved ones, then you were willing to swallow this bitter pill.
The war against All For One continued to rage on, but your quirk had helped you fight and win many battles. You were now not just famous among the people, but also among the villains that you fought against.
Fear; they feared you and your ability to kill everyone on the battlefield with the blink of an eye.
By the age of 18, you had already become the lieutenant general of the army. It was the second highest rank in the army and while it was a moment of pride, you had only seen horror throughout your time at this position.
You had lost more men and more soldiers than you could remember, at some point, you didn't even know how many people you had seen die in your hands. Every night, you were haunted by their cries and pleads, filled with misery to let them live a little longer.
But you did not know how to save someone, only how to destroy.
You would sometimes lay awake in your bed, remembering each and every life lost in front of you. You prayed fervently that at some point, you would just grow numb to all the pain that it gave you, but you never did.
The pain never faded, and it only grew with years to come.
All For One's rival was nowhere to be found, and finally... the final battle was fought.
You couldn't believe how many people you had seen, die right in front of you. People you were friends with, people you shared meals with, people you had fought alongside, people who you knew had families waiting for them back at home.
All of them, dropped like flies in front of the beast.
In the end, it was the same old scene from every battle you had partaken in. All that was left on the battlefield, was you and your enemy.
You fought with everything you had, every muscle in your body, every fiber detested that thing's existence. He was the reason why you had lost both your parents, why you had lost your sister, why you had lost your friends, your comrades, children, women, civilians....
All those lives were lost to him...
He was the reason for all their deaths.
And you were going to get your revenge, no matter what.
You fought, and fought. Every move, every twist, every strike, all of it was intended to end his pathetic life. But like a leech clinging on to it's host, that bastard clinged onto life.
For hours and hours, you fought that man. By the time you had stopped, you couldn't see from your right eye. The fingers of your left hand were completely crushed and destroyed, you couldn't hear anything from your left ear.
You had blood pouring out of the stab wounds imbedded in your shoulder, your abdomen and your legs. Every step you took sent pangs of pain through your body.
You knew you were going to die tonight.
As much as you lamented over your condition, you couldn't deny that you had also wrecked havoc upon All For One. He was completely missing his right arm, his left leg had bones poking out of them, blood was slowly oozing out of the wounds you had given him.
He was tired enough that he couldn't find enough energy to heal them.
This was your chance...
Gathering what was left in your body, you discarded the bloody weapon in your hands (it was a sword) and finally activated your quirk.
Temperatures rose higher and higher. But this time, you focused on All For One's blood.
His blood was bubbling, boiling, spilling out of the open wounds like a waterfall and you could hear him choking on it.
Had you tried this move at the start of the fight, it would have been of no use. But with how weakened All For One was at this moment, even such a simple move was doing the trick.
Dying...
He was dying, and as soon as the thought registered in your head, a sickening smile sprang on your lips, "Haha... Hahahaha!! HAHAHAHA!! HOW DOES IT FEEL, YOU SON OF A BITCH?!
No reply. Of course, how could he? When his blood was practically boiling?
"YOU FEEL THAT PAIN?! FOCUS ON IT!! THAT'S WHAT I'VE BEEN FEELING MY ENTIRE LIFE!! SO NOW, I'LL RETURN THE FAVOUR, TEN FOLDS!!" You sealed the deal by using all your energy to boil his blood to the temperature at which it would begin to evaporate.
And soon, nothing was left of him.
At least, nothing that you could see...
Your body, now at the very end of its limit, was finally about to collapse. But you dragged your body forward enough to lean against the rubble left from the fight.
"Ha... Mom, Dad.... Big Sis... I did it..." After a very, very long time, you finally smiled. A carefree smile made way to your lips as you looked up, the Sun was beginning to rise already.
Ah... It's already the next day?
Crap, you... still haven't... made breakfast...
[Brother Name], Nozomi... They'll make breakfast, right? You've worked hard enough... They'll definitely make it for you...
And just like that, at the age of 20... you had finally fulfilled your mission.
Although only temporarily, but the peace still remained...
A peaceful world, in which [Brother Name] and Nozomi can live freely, a carefree world where they don't have to steal or kill to live another day...
You were not the one who had started this war... But you were the one who had ended it, for now...