If there's something Katsuki's passionate about, it's music.
And yet…
But music's useless! A teenage Izuku would constantly cry to Katsuki growing up.
How can you say that, Izuku!? Katsuki would reply back to the weeping Izuku. No one plays the lyre as good as you!
Katsuki's fists ball.
Music's beautiful, Izuku.
"I'm going to kill him. I'm going to kill him for trading away his lyre, the one thing he's always been good at."
"But before that happens," Katsuki grits his teeth, "I'll show that moron why giving away his lyre is worst mistake he could ever made."