Chapter Text
Prologue
.
No matter where you looked, you saw only destruction and desolation. Everything was in ruins. Cities, forests, roads, everything had been replaced, turned into rubble. Rubble created by battles. Battles between Villains and Heroes. Between an immortal Villain and a young Hero.
Between All For One and Deku.
Everyone who had been present at the beginning of this confrontation was no longer there. Either dead, injured, evacuated, or unconscious somewhere. Only the two opponents were still standing, facing each other. Determined to fight. Determined to win.
Deku for peace and justice.
All For One for a different world.
.
.
For hours, Izuku had been fighting, dodging, jumping, countering, surviving All For One's attacks. No. The Supervillain had somehow abandoned his original body and transferred his mind into Shigaraki's, controlling him perfectly. This was nothing like what Izuku had faced during the Battle of Jaku, where Shigaraki fought against the mental domination of All For One's ghostly presence through the Quirk.
Unfortunately, this time, the young Villain seemed to have lost to his Sensei.
‘I have to save him!’
This situation wasn't in Izuku's favor. How could he defeat All For One if he couldn't talk to Shigaraki? How could he save him if he couldn't reach him? Izuku refused to kill him even though his body had clearly become All For One's.
Izuku was at a dead end.
And the Supervillain's speech wasn't helping. All For One kept talking about a new world, a different world, about how badly Izuku had been treated as a Quirkless, that being a hero wouldn't give him the life he deserved, that he couldn't keep One For All, that this power was too heavy, too great for him.
Izuku didn't want to listen. But if he didn't, he might miss a chance to reach Shigaraki. The teenager was convinced that the Villain was aware of what was happening, just unable to react and control his body on his own. So Izuku heard more than he listened. It had always been like this. Hearing everything that was happening around him, then piecing it all together to fill his notebooks about his heroes, his teachers, his classmates, his family, about Kacchan. His brain worked in the background on what he was hearing even if Izuku didn't want it to, his deduction and logic tidying up the gathered information.
And it was because of this that Izuku understood All For One.
The man wanted to change the world, change the system, and destroy everything related to heroes. As if he had been disappointed, as if he wanted to correct the errors caused by the arrival of quirks, but without wanting to eliminate them as Overhaul did.
And it was this contradiction that Izuku didn’t understand.
Because despite all his speeches, all his fine phrases and words, All For One never clearly stated what goals he wanted to achieve. It was always vague, imprecise. It was by remaining abstract about his intentions that he had managed to manipulate, to gather people under his control, arguing that it was for their good, for the good of the world, for the future of a new world.
Izuku knew All For One was power-hungry, especially for One For All. But Izuku didn’t know what had triggered this thirst for power, before his brother's Quirk was discovered.
The young hero was in a daze. He understood and didn't understand. He knew and didn't know. He couldn't decide how to act to create a decisive opening for his opponent so that victory could swing his way. The Predecessors only helped him with the fight itself, the First being strangely silent.
Another thing Izuku didn’t understand. And he didn’t like that. He didn’t like not understanding, because that usually meant it was bad for him.
Like now.
All For One touched him with an unknown quirk, sending him flying and crashing against a remaining piece of concrete wall. Increasing once again the level of pain he felt throughout his body. Izuku hurt, terribly so. But that didn’t matter. He was used to pain. Always had been, since his diagnosis. But pain had never stopped him from moving forward, from continuing.
Despite the pain, he had gained a quirk.
Despite the pain, he had become a hero.
Despite the pain, he was able to save people.
Despite the pain, he would stand up and defeat All For One.
Izuku was standing.
“So determined and yet so weak. Just like my dear little brother.”
All For One calmly approached, as comfortable as if he were in his living room, smiling with Shigaraki’s face. That image seemed wrong and disturbing to Izuku.
“He wasn’t weak!” he protested angrily, wiping some blood from his eyes.
Just because someone didn’t have a powerful quirk didn’t mean they were weak. The young hero fanboy had taken a long time to understand that, and especially to accept it for himself. The First wasn’t weak. None of the Holders were weak. Izuku wasn’t weak.
But it wasn’t thanks to One For All that he was- no, that they were strong. It was thanks to their will to never give up and their heart. They were strong because deep inside, they were Heroes.
Izuku was a Hero.
‘I will save him!’
“Shigaraki!!”
He launched an attack, missing his target who dodged. Izuku tried again. He continued, and continued while calling out to Shigaraki, speaking to him hoping he would grab the lifeline and surface. But nothing. All For One still controlled him, attacking, dodging, counterattacking, and mocking Izuku, telling him to give up, that Shigaraki was no longer there, that his mind was gone. The clearest proof was the absence of his quirk. Last time he had used Disintegration, even if he wasn’t directly targeting Izuku. This time, All For One seemed to never use that quirk.
Izuku dodged again and followed up with a sneaky kick, but it didn’t do much damage. He had the Shock Absorption quirk from the first Nomu, after all.
If Izuku had to be honest, he was betting all his victory on Shigaraki waking up. He didn’t know why, but he felt that’s what he had to do. Or rather, he couldn’t find any other way to win. All For One possessed all the quirks of his former body, plus those he had given to Shigaraki, which included Super Regeneration and Life Force among others. And the aspiring hero could rack his brain all he wanted, he didn’t know how to defeat someone immortal who could absorb shocks and regenerate at will. And without killing him, of course.
So there was no external way to win.
There was only one way to win.
From the inside.
[I need your help, First.]
And Izuku threw himself at All For One, completely unguarded, his mind and will fully focused on that place, that space outside of time, that place where he could reach Shigaraki. The Super-Villain, seeing a golden opportunity in this seemingly desperate action, stretched out his arm to grab him, his hand closing around the green curls.
There they were again, face to face, inside One For All, Izuku and the First on one side, All For One on the other. No sign of Shigaraki. Izuku grew worried. He couldn’t have disappeared.
“Shigaraki!”
“Don’t waste your energy. I already told you Tomura is gone.”
“That’s not true! I know he’s still there! It’s his body, not yours!” shouted Izuku, getting into a fighting stance.
The First placed his hand on his shoulder, to hold him back or calm him, the teenager couldn’t tell.
“Everything lies in will. That boy is strong, Nii-san. Everything ends today.”
All For One burst out laughing, his aura and will reverberating around them, creating powerful and intense air currents.
“Still as stubborn, I see. You should know by now that the kid hasn’t even managed to land a serious injury on me in all these past hours. He can’t do anything against this perfect body!”
“I know.” said Izuku in a calm and confident tone, surprising the Villain. “Alone, I don’t stand a chance.”
All the Predecessors appeared behind Izuku – including All Might! – ready to fight, ready to finish what began over two hundred years ago. Today, they would win.
“Even if One For All responds by drawing on the user’s will, none of you are strong enough to defeat me! Even all together!” exclaimed the Villain, spreading his arms and radiating power. “No one can defeat me!”
And he charged.
Izuku and the Predecessors charged in turn, the power of One For All in their hands.
.
.
If this had been reality, the area would have been annihilated. The shock of all these powers, of all these quirks created an immense and terrifying explosion. Every person present focused on their goal.
The Predecessors wanted to defeat All For One.
All For One wanted to seize One For All.
Midoriya Izuku wanted to save Shigaraki Tomura.
Shigaraki Tomura wanted to destroy everything.
The meeting of these wills, combined with the quirks, caused an event that absolutely no one could have foreseen or imagined.
One For All is the accidental result of a combination of two different quirks, a fusion that no one would have thought possible. One For All stores and transmits to its user the power, the quirk, the spirit of its former users. One For All is a condensation of will and energy accumulated over more than two hundred years.
To this mix were added All For One’s own specifications, completely unleashing the energies and fusing them.
To this mix were added the wills of Izuku and Tomura, giving the energies a direction, an action to perform.
Among the eleven people present in the space-time of One For All, only one was affected. The only living person as the vessel of the One For All power. Midoriya Izuku.
Silence fell. The world vanished.
And an alarm sounded.