Not a boy but the King of Curses

[1st POV]

My head was clear but my heart was painted with emotions.

As the King of Curses, I was unaffected by the negative emotions of humans. But that didn't mean I erased them.

It was like eating food without a tastebud. I was unaffected by the taste but I was still eating. I chewed, I swallowed and I was full.

Therefore, when the fight began, I was filled with cold fury. I was not holding anything back; I had been flexible enough for civilians who hated me.

But to my pleasant surprise, the first exchange of the battle told me that things were not going to be as easy as I thought even if I went all out.

*BOOOOOOM!!*

My body flew like a streak of lightning before I crashed into the side of a skyscraper. The glass and steel crumbled under my body enhanced with cursed energy as I made a gaping hole on it.

The glass cried in a shrilling sound and broke all over. The shards fell to the ground - if civilians were still here hundreds would've died.

"You didn't expect me to remain still while you go around sending threats my way, did you?" All for One said as he floated in front of the skyscraper.

"I changed my quirk set with the sole aim of fighting against you, even at the cost of abandoning splendid quirks just to amass more combat-oriented quirks," he said.

So he did have a limit to how much qurik his body could handle, or at least use simultaneously. I noted thoughtfully.

"Why are you telling me? You want my acknowledgement?" I said as I walked out of the rubble.

"Good boy,"

*BOOOOOM!!!*

The upper section of the skyscraper was completely blown off by an air cannon that was amplified by many quirks. The shockwave travelled outwards, shaking the atmosphere.

When the aftermath of the attack receded, he said, "I want you to feel honoured for pushing me to take such drastic measures. "

The cloud of dust and debris was immediately dispersed when I sent a huge slash - Cleave - in his direction. It cut right through everything around him except for himself.

He faltered for only one moment before he quickly healed the scratch on his chest. I was holding out my hand and held my posture when I saw what he looked like.

In his current form, he looked even more monstrous than I did. His body was armoured with layer after layer of defensive quirks, making him look like some kind of an abomination.

I could make out a quirk that turned his skin into steel, a quirk that produced thick armour on his body, a quirk that strengthened his bone - making jagged white stick out from some part of his skin etc.

It was because of all these that he could take my strongest slash and only suffer a scratch.

'Let's test how sturdy he really is,' I thought and shot off the building.

I could start spamming World Cutting Slash but that would not be a wise move. I still did not know the extent of his regeneration quirks - which I was sure he had. If I cut him now and he regenerated easily, it would reveal to him that I could break through his armour and he would just be more cautious.

I need to strategize.

People often mistook going all out as using everything you had to fight. No, it meant going to any length to assure victory.

And so we began fighting in the sky. It would be favorable if we fought on the ground but that would put All Might into the equation so I preferred an aerial fight for now.

The first round of our battle tore through Yokohama. All for One had the edge in the sky but I managed to keep up with him by using the skyscrapers and barriers as foothold.

It was a fight, All for One came after me just as much as I went after him.

We blurred through the atmosphere as the skyline, once proud and unyielding, collapsed in stages. The skyscrapers toppled under the invisible weight of our clash, their steel frames groaning before snapping like twigs.

Hundreds of ranged attack quirks contend with invisible blades, neither getting the upper hand as intensity cancelled lethality. Glass rained down in glittering sheets like a cruel parody of a winter storm.

All for One was no slouch when it came to raw strength either. He was not only physically formidable but he had hundreds of quirks amplifying every punch he threw and every kick he executed. I was caught more than once by a punch with the weight of a ton behind it.

We often used the buildings to hide our attacks. Concrete walls folded and disintegrated, and the cloud of dust was a smokescreen. The derbies rained down the empty streets, causing massive destruction.

The air itself seemed to detonate as All for One spammed his air cannons when he realized his other quirks had no effect. I had to use RCT more than once to heal part of my body that was blown off. The explosions in the atmosphere echoed like thunder - only sharper, louder, more immediate.

The sound was relentless. Not just the crash of steel and stone, but the high-pitched whistle. We moved through the air like living jets, breaking the sound barrier as easily as we broke the glass of skyscrapers.

We were like two men fighting in a world made of Legos. Everything was so fragile in comparison to our battle.

...

"Blackflash," I said and as if on command, a spark of lighting crackled from my fist. The fabrics of space warped as I slammed my fist on All for One's face.

My punch crushed whatever armour or defensive qurik he had and disfigured his face. He was a streak of a shooting star as he landed on the ground with an explosion.

I too landed shortly after and at last, I watched as All for One healed his injuries. It was not rewind or anything. It was a quick recovery at the cost of stamina? I was not sure but I deemed it to be not too bothersome. It was not even on the level of RTC.

All for One healed as quickly as he could, expecting me to exploit his moment of weakness but I just stared at him with contemplative eyes.

"I don't think you will survive being sliced into a hundred or more pieces," I commented offhandedly. Perhaps I need not be too cautious and shoul just spam World Cutting Slash now.

The screams of collateral damage almost died down before All Might finally reached our position. He was dressed in his blue and red costume, but unlike his other costumes, this one was now a full-body suit that covered even his face.

He looked like some flashy wrestler with Superman inspired color scheme.

He did not expect my surprise attack, nor did he expect Blackflash to be as strong as it was. Due to that, he was out from the first round of the battle.

But now that he was going to join, I would need to adjust to the new dynamic.

'Before that...' I narrowed my eyes and sent invisible slashes, the cuts were stitched together to form a cross pattern - Dismantle.

Very similar to what happened with All for One, my invisible slashes did no damage whatsoever while the structures around him were cut and turned into tiny pieces.

I was wondering why the costume was different and I guess now I knew why. The suit was designed to resist my slash attacks.

Antherite, a next-generation fabric that has special nano threads that can redistribute force throughout the body and is resistant to slashing and piercing power.

I heard about it from one of my old friends in the hero support course. It was not commercial yet but I guess they made it just for All Might as he was going to fight me.

"You know technically I am still a minor. Can I claim child abuse?" I smirked under my raised eyebrow.

All Might's titanic figure blurred at me, his speed was faster than All for One who moved like a jet. I only saw a blur of a shadow, towering over me. His 8-foot-tall figure was much larger than mine.

I threw a punch with two of my right hands, they were guided by raw instinct and wrapped in cursed energy, like my hands were on fire. The two of my fists clashed against his single one.

A massive shockwave spread around us. Solid behaved like liquid as the ground released a wave of force like dropping a pebble in a pond.

And then the earth cried as it was broken into a million pieces. All Might's punch could change the weather long after his prime and in his prime, his punch felt world-shattering.

Like literally, how could a punch pack such raw strength behind them? He had nuclear for arms.

My arm could not exchange force with such a behemoth and they exploded in a mash of flesh and bone. His punch on the other hand continued until it sank into my stomach.

The force was so strong that it produced heat and exploded like a literal bomb. I was rag-dolled across half the city.

*BOOOOOM!!*

....

I pushed myself up from the destruction, quickly healing whatever remained of my body with the use of RTC. I adjusted my broken jaw while contemplating with a straight face.

Time to do some binding vows I guess.

My domain expansion was called 'Malevolent Shrine' and as the name suggests, it allowed me to use binding vows with more ease than other sorcerers. You could say I had more affinity towards it. After all, a shrine was where you make vows to Gods.

You could say it was a passive effect of my Domain Expansion.

And so I changed the nature of my cursed technique, Cleave and Dismatle.

Cleave allowed me to send a powerful, invisible slash at my enemy. It had a limit to how strong it was and you could not change the slash.

Dismantle was a weaker version of Cleave but more flexible. I could send more than one slash at once and even stitch them into patterns, for example in a cobweb or chess pattern. This allowed me to literally dismantle things into pieces.

For this reason, I used dismantle on objects, it was weaker but still strong enough to cut through things. I used cleave on humans as it was stronger and most people die with one slash anyway without needing multiple.

That was the original nature of my technique. But I changed that into a familiar one.

Dismantle remained the same for the most part while I changed Cleave. In exchange for it being a projectile, I increased the upper limit of Cleave as much as possible. Almost to the point that as long as I put more cursed energy, I could cut through anything.

I would need to touch my target for Cleave to work from now on. I also added the condition that cleave would adjust automatically to the toughness of my target. That way I would not need to focus on that during fast-paced battles like this one and also not waste massive cursed energy on cutting up weak targets.

It was exactly the same condition as Sukuna put on his cursed technique in JJK. He did that when curses were not his only enemy anymore and he needed to fight against other sorcerers more efficiently.

The moment I was done with my binding vow, All Might all but blitzed towards me with AFO coming right after him.

I dodged their combined attacks with acrobatics and trusted my battle instinct to guide me when my eyes failed. I played with my adjusted cursed technique in my mind and my fighting style adjusted easily enough.

It could be said that I had more experience using this version of Cleave and Dismantle than their original version.

So when a hook from All Might came blurting at my face, I stopped towards it. I disregarded the natural instinct to move away from death and dived right into it.

I stopped the hook from its origin which was All Might's shoulder. My two hands blocked the weakened hook while the others grabbed his shoulder.

There was a muffled explosion of suppressed force and then...

"Cleave,"

The fleshy sound of something being sliced off echoed through the vacant city. All Might stumbled back, liquid red spilling out like an uncontrollable fountain. His blue eyes widened in horror as he looked at his shoulder.

There was no longer an arm connected to the shoulder.

A sense of glee and satisfaction filled my entire body. It was like the most addictive drug.

AFO and All Might watched me in a mix of horror and surprise while I slowly brought up the muscular arm.

I used cleave once more to cut the arm into pieces like cutting a carrot on a chopping board. The discs of flesh fell on the ground, painting it red.

All Might finally grunted and went down on one knee, the agony that flashed on his face was mixed with fear. AFO was not feeling much different.

I capitalized on their fear by releasing my cursed energy. The full weight of my curse slammed on their shoulder.

It must've felt like they were looking at the source of all evil itself. Curse energy was but a culmination of all negative emotions and I had a country's worth in me.

All Miight's eyes flashed in stubborn blue. I could see in his eyes that I just confirmed what he had been a bit hesitant to believe.

That I was not human.

I didn't care though.

I blurred towards the kneeling All Might and I touched him to create another cleave at his abdomen. This time I did not cut through him as he defended with- I didn't know, probably some bullshit plot armour.

But the invisible slash carried him away with breakneck speed.

"I wonder, what exactly are you?" AFO asked as All Might sailed and broke through multiple buildings in the distance.

I did not answer and the battle continued - well, if your opponent running away could be called a battle that is.

...

...

...

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Author : I just want to mention that I am not all knowledgable, I am but a casual fan who enjoyed JJK and MHA. So if you find any mistake, just consider them as an AU. 

And I made some mistake on Cleave and Dismantle earlier and I explained it with this. I've done my research this time so this should make sense.