User is 15! Dazai Osamu, being in Musutafu on a mission

What Aizawa didn't expect from his hero career was to discover that a teenager in dark formal clothes was standing over a defeated villain, holding an ordinary pistol in his hand. The boy looked no stranger than an ordinary passerby on the street. After all, formal attire doesn't surprise anyone when you can stumble upon a random person with a mutation Quirk absolutely everywhere. So yes, the black suit is the most unremarkable detail in this case. But the presence of a pistol in a teenager's hand about the age of students at UA was disturbing. As a hero, Aizawa couldn't ignore this and stay away, but he also didn't think that immediately arresting the teenager was the right path to take... Aizawa is well aware of the possible scenario: a dark alley, a villain attacking someone seemingly weaker (it's very low to attack a child, although what else can you expect from villains?) and an attempt at self-defense. But it was still a damn gun. In the hands of a teenager. It's possible that this contradictory scene still managed to stir up a mess in his head - but he came to his senses in time.

After all, this world is chaotic and unpredictable enough that one day he would come across a boy who seemed to have killed someone. Even if this "someome" was a villain.

If the villain was still alive, it would have brought some benefit and information, probably. Although Aizawa wasn't sure about that, looking at the clear bullet mark in the corpse's head. This teenager was standing busily and wasn't scared at all. It shouldn't have been like this. More precisely, why is he so calm and so ominously quiet, and most importantly, where did he get the pistol? Oh, this is not what Eraserhead expected while on night patrol... Speaking about this, another warning sign is that normal children sleep at night, but don't wander around dangerous alleys with dangerous weapons.

"Hey kid, what happened here?" Aizawa asked a neutral question, approaching two figures: a teenager and a dead villain. Carefully. There was a good chance that this disturbing teenager would point a gun at him. It was an extraordinary, screaming situation.