Well, Katsuki anticipated something like this - wild movements, a retaliation, born of the anger and desperation from being blinded. He has no idea what old wound he opened, not privy to that sort of thing, but he does know things are going to be a razor's edge from now on. The young Hero has to act, and he has to act quickly and without hesitation if he wants to cinch this.

"Tch...creativity's not your strength, is it?" Because he's heard that shit a thousand times. Empty threats made toward him or any one of his friends. He's utterly shaking, truly.

Leaping from his position, and to avoid a flurry of flame and rocks coming his way (the last point where Emet knew he'd be), his mind starts to whirr with any strategy he can think of to close in and knock this guy out. He's got elements magic, shields, and also the robot's basically a bodyguard as well...probably covering any blind spots the guy's got. Hm...this won't be as easy as he anticipated, especially cuz he can't kill the guy, just his stupid bot, but he's never shied away from a challenge.

Waiting for an opening, Katsuki tests his luck, attempting to fire an AP Shot - a much more dumbed down one, since he's not aiming to blow the guy's limbs off, just injure him enough not to stand - at one of his aforementioned legs, or even a knee. Anything he can do to get the bastard on the ground long enough to tackle, pin, and knock him out. Or just slow him down.