An explosion wakes Mikoto up from his nap, as he looks over at the source he sees Midoriya and Bakugo arguing over something, well arguing isn't the right term as Bakugo is just bullying the young protag while said young protag cowers in the corner.
Mikoto-" Bakugo lay off the nerd, You won't get into U.A. if he ever reports this shit."
Bakugo whips around ready to yell something back at him but the back half of that sentence causes Bakugo to freeze in place and then robotically go back to his seat, seemingly contemplating the validity of that statement. Mikoto, satisfied to have completely shut down Bakugo, takes out a cigarette and lights it with his power.
Teacher(Unnamed, Who gives a shit anyway)-" SUOH, NO SMOKING IN CLASS, you can't even have those legally, how did you get them?!"
Mikoto-" Bite me Prick, I do what I want!"
His aura then roars to life causing the teacher to fall to his knees and all the students, excluding Bakugo, follow suit. The teacher gets up after Mikoto's aura subsides and sighs to himself, this routine happens almost everyday all the other teachers already gave up on trying to stop the boy, most infuriating to all of them was that Mikoto was a straight A student and had an amazing quirk, so they really couldn't do much to stop him anyhow.
After finishing the school day out Mikoto walks home, keeping up-to-date on the news on his walk so he doesn't miss the coverage of the sludge villain incident. Suddenly the city block he is on rocks as an explosion goes off, Mikoto whips around to find the source of the explosion and as luck would have it, it's the sludge villain. Originally he wasn't going to help as he didn't know where the incident would happen and he knew Bakugo would be saved but seeing it so close Mikoto can't help but run over to watch it all go down.
He watches the scene, it going down as he remembers it but then Bakugo's eyes show through the sludge and Mikoto's instincts can no longer ignore the child in danger infront of him so ignoring his knowledge he launches forward as Midoriya does the same.
Mikoto-" Midoriya, distract the villain I'll deal with him after I deal with the fire, got it?"
Izuku-" Huh? Suoh what are you doing here?!"
Mikoto-" Helping dumbass! Now answer me, do you understand the plan? Can you do your part and distract that villain long enough for me to help you get Bakugo?!"
Izuku-" YES!"
Mikoto does a nod in acknowledgement then splits from Midoriya running over towards the fire. Once he gets within range he uses his power to suck all the fire and smoke towards him and absorb it, the process only takes a few seconds but Izuku barely can manage for that long. As the Sludge villain moves to slap Izuku Mikoto launchs forward, his aura on full blast and a set of fire wings on his back as he safely grabs Bakugo and then bursts the Sludge villain into pieces with a boosted Flame Slash. All Might doesn't even get the chance to step onto the field.
10 minutes later Mikoto is getting praised for his power and quirk usage, even if it was illegal, meanwhile Izuku is getting Chewed-Out.
Mikoto-" Death Arms right?"
The man chewing Izuku out turns toward Mikoto and chuckles, nodding, but before he gets to praising Mikoto he is interrupted.
Mikoto-" Retire, You and the rest of the heros here should retire before you slander the label anymore, all of you should get a new job that means your incompetence won't risk so many lives or so much public property."
The Heroes all look at him slack-jawed and before they get a word in Mikoto turns, lights a cigarette, and then walks off. His cigarette and his power covering his silhouette in smoke.