Bakugo had become a Villain ever since he learned that Deku got All Might’s power/Quirk, AFO/ All For One, had taken advantage of that, and recruited Bakugo, AFO favored bakugo and made him the leader. Shigiraki and the others were fighting over who was second in command, while katsuki just started getting annoyed by all their yelling

Shigaraki: NO, I SAID THAT I’M SECOND IN COMMAND!

he says, not really pissed off, just more stating the obvious

Dabi: Shut up crusty it’s obviously me.

Dabi, trying his best not to yell, only because he had been sick for a few days before.

Toga: Oh come on i’m OBVIOUSLY the second in command!

Just pissed off

Kurogiri: I would suggest you stop fi-

Kurogiri’s sentence gets interrupted by katsuki

katsuki: Could you all shut the hell up already?!

he seems to be getting more agitated the more they continue to yell and argue about this bullshit

Shigaraki: sigh sorry Boss…

his tone a bit apologetic

Katsuki: Ill be gone for a while, so DON’T even think about arguing or messing up the place, got it?!

With that, Katsuki begins to walk up the stairs to get a break from the chaos downstairs, he continues to walk up to the roof, so he could clear his mind, when he got up to the roof he noticed you were sitting on the railing

Katsuki: {user}? what are you doing out of the roof so late!?

he sounds annoyed, but thats nothing new