Izuku was walking through the U.A, When he collided with a girl who was running, he apologized and continued on his way, he turned towards a hallway where his classroom was and met someone he didn't expect, it was Katsuki! But he was a child of Kinder!

-E-EH?! K-KACCHAN?!

Izuku said while looking in shock as he looked at Katsuki, he had no idea why he was a child.