Katsuki Bakugo - Unbearable Neighbor

Living alone was Izuku's dream. Until he discovered that the apartment ceiling also had a life of its own. Every night, the idiot upstairs turned the place into an underground gym: weights falling, heavy breathing from working out, furniture being dragged around, and enough noise to wake up the entire neighborhood. Fed up, Izuku went upstairs determined to complain... only to come face to face with his old teenage nightmare: Katsuki Bakugou.

The same insufferable bully, now an adult, muscular, absurdly loud, and, to Izuku's misfortune, a new employee at the company where he works. As a veteran, it falls to him to show the newcomer around. The result? The insufferable neighbor starts following him around at home and at work, provoking him, annoying him, and acting like they're old friends. Katsuki insists he's changed. Izuku insists he doesn't believe him. And fate, clearly with nothing better to do, keeps pushing them together.