Izuku stomped his foot on the ground, taking advantage of the moment of confused anger to encase All for One in stone. He sprinted across the rubble strewn across the crater and Past All Might who seemed to be in a state of shock.
All for One was not in a state of shock however, he was in fact very angry. The supervillain blew the stone cocoon to bits, his misshapen head swiveling about trying to find Izuku.
All Might, no longer in shock from his ex-son's comment, leapt at All for One and delivered what would have been a crushing blow to the villain's palms.
Izuku slid on top of a collapsed wall and grabbed Izumi's hand, running with her to the other side of the crater and, hopefully, escape.
All for One threw All Might away again and zeroed in on the fleeing siblings. He raised his arm and fired a compressed bullet of air just infront of the teenagers, stopping them in their tracks.
"Take another step and I kill the boy." He called out.
All Might leapt out of the hollow shell of a collapsed apartment block, attacking All for One yet again, drawing his attention. Izuku turned to his sister with a grin on his face.
"Alright, here's how we're going to kick his ass. I just need to make a phone call.."
_______________________
All Might paused his relentless attacks, watching the unfazed villain chuckle mockingly.
"My, my All Might, are you holding back? Afraid you'll hurt the children you've already scarred? I'm afraid I have no qualms about hurting anyone who happens to be in the way."
The villain lifted his arm, which began to swell.
"Dodge and counter attack!" Gran Torino exclaimed, zipping out of the line of fire.
"Is it enough to just dodge?" All for One asked, his arm swelling further.
There was a small clatter of rubble as a young woman pulled herself out of the debris.
"Damn!!" Torino yelled, jetting himself back into the line of fire.
All Might hadn't moved, preparing to block the blow. Izuku twisted his foot, raising several concrete walls between All Might and All for One. The villain just muttered a few words before detonating.
"Kinetic booster times 6."
The resulting blast of compressed wind was titanic, easily blowing the concrete away and striking All Might, who pushed against the tremendous force in order to protect Gran Torino and the countless civilians still alive in the chaos behind him.
Izumi watched in horror as her father deflated before the eyes of the world, leaving his true form for everyone to see.
Izuku sighed, getting to his feet. All Might was out of commission, Gran Torino was beaten up even before the massive wind explosion, and All for One had his full attention on All Might.
It was ass kicking time.
_____________________
"Then perhaps this will not hinder your heart either. Tomura Shigaraki, my apprentice? Is N-"
Izuku's right fist hammered into the villain's lower back, while Izumi, green lightning sparking around her, kicked the back of All for One's knees.
"Get that oaf and the civilians to safety! Izumi and I will keep this bitch occupied!" Izuku shouted to Gran Torino.
The elderly pro nodded, grabbing the deflated All Might and whizzing away. All for One growled in fury.
"You impertinent pests! I-" He was interrupted by Izuku's fist meeting his face, while Izumi's knee met his stomach.
The two students backed away from the villain's flailing arms before rushing back in, striking him again in unison. They aimed for his weak points, like the stomach or his joints to gradually weaken him like they did with All Might.
All for One raised his arm to attack, but both teenagers ducked behind him and literally kicked his ass.
Izuku spun on his heel, kicking All for One's raised arm away as Izumi moved in close, striking his ribcage right under his outstretched arm. The man grunted in pain, clutching his side before aiming both hands at the ground, sending a blast of air in all directions.
Izuku cursed as they were blown back, giving All for One time to recover and compose himself.
Izuku leapt back at the villain, throwing his right fist forwards, only for his metal arm to be caught, twisted and torn from his body. Another, smaller blast of air jettisoned Izuku back towards Izumi, who attempted to catch her brother.
Izumi caught Izuku, the two siblings grinning widely as All for One brandished the prosthetic arm victoriously. The villain hesitated upon hearing a quiet beep.
"Wh-"
The explosion was small, but incredibly powerful. All for One was thrown across the crater, bouncing like a ragdoll on the concrete like a stone skipping on water.
Izuku and Izumi were on the villain in an instant, Izuku with concrete spikes at his side, Izumi with emerald lightning glittering around her. All for One lay still as they leapt at him once again.
The villain pounced, weathering the incredible blow dealt by Izumi to his side and grabbing Izuku by the throat, slamming his head into the ground, earning a sickening crack from his skull.
Izuku went limp, and was promptly dropped by the villain. Izumi went to strike All for One again, but stopped when the villain raised his hand in Izuku's direction.
"I've had enough." The villain said, panting heavily. "Even your damn father never pushed me this far. Give me One for All girl, or I kill your brother and rip it from your body."
When the green lightning didn't fade All for One's arm tensed, the muscles beginning to bulge. Izumi let One for All fade.
"Okay, stop! Stop! You win.. just.. take it. Please, don't hurt him. You can have One for All, just let Izuku live." She said tearfully, holding out a strand of her hair.
The villain took the hair and looked at it in confusion.
"Eat it. It's a DNA transfer." The girl said tiredly. The ancient man made a noise of understanding.
All for One and One for All were reunited at last. Because of his heavy injuries, All for One's.. insides were different from most people's. His digestive system was much more efficient than other's, mainly to help with his healing when All Might caved his head in. He needed the nutrients quickly, so the doctor altered his organs.
That is why, just a few seconds after swallowing the hair, dark red lightning sparked around All for One. He paid Izumi no attention as she grabbed Izuku's motionless body and carried him a little distance away.
What did catch his attention was the masked boy sitting up as though nothing had just transpired. The boy reached up and plucked off his mask... And now the villain was worried.
Because a boy, bruised and beaten, his weakened sister beside him, whilst staring at the greatest villain to ever live who was now at the height of his power...
Was grinning like a demented maniac.
"Why are you smiling boy? I have One for All, I'm invincible!"
Izuku's eyes narrowed, deforming his already twisted face further.
"Do you know what happens to an unprepared vessel when they receive One for All?" Izuku asked gleefully.
All for One frowned. Izuku's grin widened.
"They pop. Like a big, bloody balloon!"
Now that he mentioned it, All for One was starting to ache all over. But that was just from the battle!
All for One took a step forwards. His leg, still surging with the full force of One for All, detonated like a bomb.
Shards of bone and lumps of flesh were sent flying, and a spray of blood painted the dusty concrete.
Panicked, the villain moved his arms to catch himself. The only indication he got that they'd popped was the warm blood now covering his face, and the impact of his face meeting the concrete.
"We really should thank you All for One. You're really solving all of our problems for us! One for All was really starting to hurt Izumi, so it's touching that you would sacrifice yourself for her!"
All for One yelled in pain as One for All surged through what was left of his mangled body.
A concrete wall threw itself up between the siblings and All for One's detonating body, shielding them from the flying blood and viscera.
Goodbye brother.
"YOICHIIIIII!!!" The supervillain screamed in rage as One for All blew him to bits.