It ends at a specific chapter, but I can't recall exactly off the top of my head. You might want to check online manga forums or dedicated One Punch Man fan sites for the precise chapter.
Well, in the 'One Punch Man King Side Story', it shows King's side of the story. King is sort of a false hero in a way. He's always at the right place at the wrong time. The side story could involve his interactions with other heroes or monsters. For example, when other heroes look up to him, he has to pretend to be confident and all - knowing. And when facing monsters, he somehow manages to get out of dangerous situations without actually having any real combat power, which makes for some really interesting and funny scenarios.
You can find 'One Punch Man' fanfictions on websites like FanFiction.net. It has a large collection of fan - created stories related to 'One Punch Man'. There are different categories and ratings, so you can easily filter and find the ones that suit your taste.
One Punch Superman was now finished. Although the story was very exciting, due to the limitations of the story rhythm and battle scenes in the manga, the development of the story did not reach the height of animation. Therefore, some people thought that it ended in a hurry.
There was no official news on whether there would be a second season. However, the original manga of One Punch Superman had received a lot of attention and love from readers in the past few years, so if the animated version could be successful enough, it was likely that there would be a sequel.