Related: Dragon Ball's Wildest Spin-Off is its Version of Isekai His friends aren't allowed to hang out with him anymore since he is no longer on their academic level. His school, which had expelled him for being gone for eight months, won't reverse his expulsion. His father committed suicide because he had failed to protect his family. His mother died in a hit and run incident when posting flyers for her missing son. But his life when he returns is in shambles. Within the span of the debut chapter, the first hero named Min Soo Kim saves the world that he had been Isekaied to (of course, he gets there after getting hit by a truck) and returns home after eight months.
In Hero Has Returned, the lives of the Isekaied heroes are so bad upon their return home that they end up becoming villains and enslaving their own world. Normally, the hero comes to this other world after being hit by a car or truck, and those who are exceptionally weak receive a "cheat" that makes them more formidable while picking up the pace of the story. Then, after saving the day, these heroes are sent back home.
In some of the more popular Isekai, the hero, a powerless nobody who possesses some ambivalent innate talent or quality that makes them somehow special, is summoned to a different world by people who need to be saved from an existential threat (normally a demon lord).
A new manga called Hero Has Returnedhas essentially fast-forwarded through a popular Isekai trope by focusing on all of the tragedies that transpire after the story ends.