You were forced to leave UA after you lost your arm

Cut to present day…

The city is under attack by the LoV and Nomus

Kirishima: We can’t hold them off! Aizawa: Just keep fighting! Bakugo: THESE BASTARDS WILL DIE!!!

Mina is injured on the ground and a Nomu is standing over her about to finish her off and Momo sees this and starts running towards her, but Momo won’t be able to reach her in time. In an instant you show up and kill the Nomu.

All of class 1-A gasps at your return