PROJECT: MONSTER CLASS (My hero academia Kaiju AU)

Prolouge: All Might vs Overhaul

???: You don't know when to give up, do you?

In the distance, two figures could be seen fighting. One figure was pale man with black hair and a green coat. His most noteworthy feature is his giant plague doctor mask he's wearing while fighting the other figure. He rushes to the other figure but keeps missing him. This was the pro villain and leader of the Shie Hassaikai, Overhaul.

???: Hah, a real hero never gives up, even when staring in the face of death. Just make this easy on everyone and turn yourself in Overhaul.

The other man in question was a giant blonde buff hero. He was wearing a red, blue and yellow hero suit, with two strings of hair standing up high. Even though the man looked both strong and intimidating, he had a warm and calming aura around him and he was smiling at the villain. This man was both the #1 hero and world's symbol of peace, All Might.

Overhaul: Tch, don't you see All might?!? The world is impure, the disease that are quirks has plagued humanity with impurity! I seek to cure that impurity and make the human race pure again! 

All Might: You're wrong Overhaul, quirks are very beneficial to today's society. Without them, we wouldn't be able to achieve half of what is possible today!

Overhaul: Really now, tell me how do you think villains are made? Your 'perfect society' praises people like you for having flashy quirks while they beat and ignore people with villainous, weak or no quirks. Don't you see All Might?!? Our society is dependent on quirks and I aim to purify society and restore the glory of the Yakuza!

All Might: While I do agree that about the negative effects of quirks on society, it's my intention to give peace and hope to the people of the world. As the world's symbol of peace, it is my job to give everyone, quirk or no quirk, a bright future to look up to. Starting by taking you down!

Overhaul: So be it. . .

As he said that, Kai began mutating. Giant pieces of flesh, arms and other limbs began sprouting out of his body. As more limbs began sprouting, he began growing in size. All Might noticed this and began moving back to gain distance from the growing behemoth. As he began growing into his final form, Overhaul began growing a bird like head and sprouted two giant wings from his back. His body a glaring red with the bottom side of being ribs protecting something. When the thing roared, it revealed Overhaul stuck connected to the inside of the beast.

All Might: What in the-

Overhaul: Well, what do you think All Might?!? Before our battle, I managed to merge myself with two other members and a little something as well. These wings you see here originally belonged to an ancient dragon that fell here years ago. Now, let's end this!

All Might quickly jumped out of the way as a giant hand smashed down on where he was just standing.  After regaining some ground, he began running towards Overhaul at full speed.

All Might: CALIFORNIA SMASH!!!

All Might had punched one of the legs of the giant kaiju-like monster that was Overhaul. Overhaul retaliated with by attempting to smash All Might with one of his arms, all of them seemingly missing him. All Might than preformed the same move two more times on his other legs, leaving him unbalanced. Before All Might could attack another arm, he was shot by what seemed to be a red lightning bolt. He looked up to see Overhaul now using his wings to lift himself in the air and firing that same red lightning straight at him.

Overhaul: You see that All Might? Now this is the full power of the dragon of destruction, DESGHIDORAH!

As he said that, his beast form emitted what sounded like an elephant like roar form where it's mouth should be. All Might began moving from area to area to avoid the red lightning that Overhaul shot out from his kaiju form.