Aonuma Yuuki

It's been made into a novel! An anime! And, something no one expected, it's now been made into a vertical manga! With his sloppy white coat and dead fish-like eyes, Sakata Ginpachi has a personality and appearance that are hardly befitting of a high school teacher. His homeroom class, Class 3-Z of Gintama High School, is crammed with students with equally strong personalities, turning it into a terrifying amusement park. Is there really a future for such a problematic class?! The spin-off of the hugely popular comic and anime "Gintama" has landed on Jump Toon for the first time! (Source: JumpToon, translated)

When Izumi Shiori's father is transferred away for his job, Izumi wanted to stay to finish high school so he moves in with his cousins. The younger cousin Joe was just like how Izumi remembered him, but the older cousin Karen has become a beautiful young woman.