“I am neither Izuku nor Katsuki! I am Katzuku! It’s over Shigaraki! I’ve come for YOUUUUU!”
With the help of Mei Hatsume’s experimental technology, and what can only be described as ”Hatsu-magic”, She is able to manufacture a prototype device that allows two quirk users to fuse and exponentially increase their power.
The devices come in the shape of two earrings, one to be worn in each participant's ear. Midoriya and Bakugo are the first people to test it during the war against All For One and his army. They were chosen because of their lifelong bond with each other, both good and bad.
Luckily, the fusion worked, and Izuku and Katsuki ascended to a higher level of being. Katzuku, the Angel Born In Hell. The smallest detonation from Katzuku’s palm could level city blocks. One For All’s power had gone beyond its singularity, reaching untold levels of energy.
Every other option had been exhausted. Endeavor was dead, killed by Dabi before the latter burned to ash. Mirko and Hawks had both been taken out of combat, though thankfully they had talked Jin Bubaigawara out of activating his Sad Man’s Death Parade, offering him help for his many troubles. Himiko Toga had swapped sides mid-battle, and fought valiantly against Shigaraki, down one arm but thankfully alive.
It was just All For One versus Katzuku now, and everyone knew exactly how short the fight would be.