The Leagues were losing their forces one at a time as the battles continued, and then you had no other choice but to take down All For One. 

(Y/N): All For One. I've grown sick and tired of this. 

All For One: Don't you ever get tired? No matter how many times I beat you down, you just keep getting back up to oppose me. It really disgusts me. 

(Y/N): Everything you have done. All the people you have destroyed, the lives you have ruined, the places you have destroyed, I'll make you pay for all of it! 

You activated Full Cowling mixed together with SSJ3. Then built it up with some Kaioken and Aura into your body. 

(Y/N): This is where everything ends. 

Back with Izuku and Shigaraki... 

The two continued their battle across the city. 

Shigaraki: Just give it up! I can see those damn ghosts in you and (Y/N) (L/N). I'll destroy you all in one go! Spinner is waiting for the horizon that I'm going to make! And it all starts and ends here. 

Izuku: I know ... deep down, your humanity is still there. MAXIMUM FA JIN! 

(Y/N): MAXIMUM GEAR SHIFT! SMOKESCREEN! 

You and Izuku both went all at it! 

https://youtu.be/Htl9NYmCo2k

The battle was being broadcast everywhere. Both from your side and Izuku's side. 

(Y/N): PEOPLE LIKE YOU NEVER WIN! YOU ALWAYS KEEP TALKING ABOUT HOW YOU'LL DESTROY EVERYTHING! THERE ARE FOOLS LIKE YOU WHO KEEP USING OTHERS TO DO WHAT THEY CAN'T DO FOR THEMSELVES! TEXAS SMASH!!! 

You kept hitting All For One. 

All For One: HOW DARE YOU! I AM THE DEMON LORD! THE ONW WHO WILL DESTROY EVERYTHING! 

He punched you, but then you smirked. 

(Y/N): Is that the best you can do? GUM GUM RED SMASH! 

You punched him in the stomach, sending him flying! 

Back with Izuku... 

Izuku was getting hurt from the recoil. 

Shigaraki: Reinforcing your tendons and muscles from the inside. I can now see that thing through your skin. Honestly, an attack like that would have caused me more trouble. You just have too much you need to protect, Midoriya. But you should know, that little boy stopped crying a long time ago. He changed the lens through which he sees the world. And he became Tomura Shigaraki. There is no suffering left inside of me! 

Izuku: I won't stop fighting until I break through to you! 

He then transformed again! 

Shigaraki: Heh, looking at you, I'd never guess you're a hero. Fine, I'll just keep destroying, you, this country, everything! 

Izuku: SMOKESCREEN! 

Shigaraki cleared it away with his flesh, but then Izuku came in and delivered a punch right to the chest! 

Yoichi: Keep going! 

You punched All For One in the face! 

(Y/N): I WILL NOT KNEEL TO YOU! 

Bruce and Ken: DON'T STOP NOW! 

Izuku: I WILL PROTECT EVERYONE! 

Hikage: Take them out!

(Y/N): NOR WILL I LET ANYONE KNEEL TO ME! 

Banjo: KEEP FIGHTING KID! 

Izuku: It's not enough until you finally accept it! 

En: Don't give up. 

Nana: GO FOR IT!!! 

(Y/N): BUT ABOVE ALL ELSE, I WON'T FORGIVE YOU, FOR MAKING MY LOVED ONES CRY!!!! 

You delivered a critical blow to All For One's stomach with his body cracking. 

All For One: ARGH! How can you have this power?! 

(Y/N): This power is all me. 

Everyone kept watching. 

Ruby: That's- 

Ochaco: (Y/N) and Deku ... they're fighting out there. 

Weiss: (Y/N) ... Izuku. 

Shoto: Don't give up ... either of you. 

Yang: Hey, Katsuki, are you- 

Katsuki was up thanks to Edgeshot. 

Katsuki: Izuku. DON'T GIVE UP YOU DAMN NERD! 

Yang: BOTH OF YOU! TAKE THOSE FUCKING ASSHOLES DOWN! 

Back with you... 

All For One's body was cracking as you kept punching him over and over. 

All For One: This can't be! This isn't my destiny! 

(Y/N): Your ideals, your dreams, they die here, ALONG WITH YOU! 

You grew extra arms out of your body and proceeded to pound All For One over and over again with everything you had! 

You then charged up everything you had, at the same time that- 

Back with Izuku... 

As Izuku kept attacking Shigaraki, he then saw- 

Man: That wasn't your grandmother. That woman was a monster who abandoned our child. Do you really want to know what heroes are? They're people who hurt their own families only to help complete strangers! 

Izuku: STOP! 

He rushed towards the man who was about to hit the young Tenko Shimura, but then- 

Nana grabbed him. 

Nana: Kotaro, I should have come back to you. If only I had, then this wouldn't have happened. I'm ... so sorry. 

Izuku then grabbed Tenko. 

Tenko: Why? 

Izuku: Because you're crying. 

Tenko: I chose to do that! I destroyed my house and my family of my own evolution! Why did I even have those hands? Who would be able to explain why I was born this way?! JUST GET OFF OF ME! 

He then turned into Shigaraki, whose body was shattering. 

Shigaraki: Even if all of my hatred went away, and I became this empty shell, I still need to become a hero to the ... villains. Hey ... Midoriya. 

His hands disappeared. 

Shigaraki: If Spinner is still alive, tell him that Tomura Shigaraki fought until the end to destroy. 

Izuku: And you did it. 

With that, Tomura Shigaraki faded away. 

He was finished. 

At the same time... 

(Y/N): UNITED STATES OF WORLD SMASH!!! 

All For One then saw all of the previous users behind you. 

All For One: This can't be! How is this- 

Yoichi: Accept it, brother, you must pay for all of the crimes you have committed for your sake. 

And then with one more hit, you punched right through him! 

All For One: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARGH! 

(Y/N): It's over. Rot in Hell, All For One. 

His entire body cracked apart, and he disentigrated. 

In Remnant... 

Death Knight: Damn it. 

Salem: All For One has been defeated? 

Death Knight: Yes, Lady Salem. (Y/N) (L/N) and Izuku Midoriya, they have defeated both All For One and Tomura Shigaraki. 

Salem: How troublesome. Still, there are other threats for them out there aside from us. 

Death Knight: Yes, the Mad Titan, the New Gods, the Dark Warriors, the False Heroes, and even the dreaded Empire of Conquerors. 

Salem: Indeed.