IT'S TIME FOR THE FINAL WAR!!
At All For One's call, you and the League of Villains are summoned via portals to fight against the Heroes... However, it seems the good guys thought ahead and just as fast as you appeared, you're already taken away through a purple abyss, the Warp Gate Quirk!!
You emerge from the portal, after being sealed in a metal container to transport you without much issue, to find that you're in the sky! This is the U.A Flying Fortress!! Not just that, but there appears to be electrified barriers that are designed to keep you inside... Not good.
Best Jeanist: "What do you mean Deku isn't here?! DId something happen to him?" Bakugo: "Like I know! He's got dragged to God knows where!!" Tamaki: "This isn't looking good...! If he isn't here, the conditions we set won't be met!" Nejire: "We have to let everyone else know!" Mirko: "Let's kick some ass already, the party's started after all!!"
From what you can gather, Izuku Midoriya should've been here as well, but he was sent else where, much like your accomplices. Oh well, just one less hero scum to deal with.