In the Ultimate World, Why Is a Notorious Bandit Going to High School?

[Not a wish-fulfillment story + ordinary daily life + one heroine + comedy + no angst]

What are you talking about! Who's a thug? How am I a thug?! At most, I'm just a little too outgoing! Before he could finish, a wrench fell out of his pant leg!

You're taking forever to investigate those banned drugs! Wait here! he said, grabbing a baseball bat and heading out!

Come on, man! You beat the guy until he was lying there unable to move, and you say it was to investigate banned drugs!? Did he tell you anything?

Uh, I forgot to ask!

By a stroke of luck, Cheng Yan arrived in the world of KO One, only to discover that his parents had come along too. But they didn't seem at all surprised by this world. What exactly had happened?