Katsuki and Izuku were passing notes in class:

_ | hey kacchan? | | yh nerd? | it's bothering me again. | | wym?? | yk. | | oh | | yh.. | dek— izuku, don't worry | i'm alive now, aren't i? | | you didn't fail me. | | | but i feel like i did. | | i keep getting flashbacks :( | | | we're talking after class. | | | okay.
—

Months have passed since the second war. When Katsuki died — And it still haunts Izuku to this day, and he blames himself.