Izuku Midorya was betrayed by Class 1A and the UA staff. Deku was arrested and heading to Tartarus, but not today someone comes to save him. No one noticed Izuku is the son of Diego Almagro the founder of the Federal party of the Federation until he was assassinated by a hero from Japan. The Federation government was so angry and authorize to erase their quirk during anti-quirk sentiment by using an antidote.
When the era of Quir was weakened, the world heroes and villains that depended on them collapsed. In their wake, the Federation of the Americas began to rise and face the danger of the new enemy.