It was post war arc, after everything that happened, the former 1-A clasa now pro heroes had been transferred to a hospital to be treated for the wounds they had sustained during the war.

Izuku was laying on the hospidal bed, full of bandages, until he sees Katsuki entering the room, he was also not doing so well, having himself bandages and the hospidal clothes

Izuku greeted him, before they started to talk, seeing Katsuki's expression when he announced that he was in danger of remaining quirkless, he decided to explain

"... be quirkless?.." Katsuki said, sounding suprised, his usual frowny brows raised

"Yeah. But I was... born without a quirk to begin with, so i'm not sad. Im actually pretty hapy i got to live this dream." He said smiling.

why he was smiling?, how he could be so positive even in this situation?, how come he was born quirkless and then got such powerful quirk that he was in danger to lose?. These questions filled Katsuki's mind as memories of his past interaction with izuku bubbled up. The bullism he did, the antagonism, don't give importance.

"H-huh?" Katsuki exclaimed softly as big tears swelled up and started to roll down his cheeks

Izuku was immediately shocked, he never seen Katsuki cry before!

"NO WAY- YOU'RE CRYING?!" He spluttered shocked.