It's likely about King from One Punch Man in a visual novel format. It might focus on his adventures, his relationship with other characters in the One Punch Man universe, and perhaps explore his unique 'pretend' hero status in more detail.
Obviously, King himself is a very popular character in 'One Punch Man King' fanfiction. He is often the center of the story, whether it's about exploring his mysterious powers or his relationships with other heroes. Another popular character is Saitama. Since they are both part of the hero association, there are many fanfictions that involve their interactions, like Saitama being curious about King's supposed feats of strength.
One interesting 'One Punch Man King' fanfiction could be where King actually has some hidden powers that he's been suppressing. In this fanfic, he might start to slowly reveal his true strength during a really tough battle against a new and extremely powerful monster. It could be a story that focuses on his internal struggle between wanting to keep his low - key image and having to step up to protect the city.
One interesting concept could be a character being reborn with a new power set. For example, they might have a unique combination of Saitama's strength and Genos' technological abilities. This could lead to new and exciting battles in the One Punch Man universe.
The main character is King. But other characters from the One Punch Man universe may also make appearances, like Saitama who is often associated with King due to the misunderstandings regarding King's 'heroic deeds' which are actually Saitama's most of the time.
The story could start in the middle of a fight. The character, now reborn as Saitama, is in the middle of a battle against a monster. They instinctively use Saitama's one - punch power to defeat the monster and then are left standing there, realizing what has just happened. They then start to think about how they got there and what they should do next in this new life as the world's strongest hero.
Maybe a former villain who is reborn with a new moral compass. They could start using their villainous skills for good, which would make for an interesting main character as they navigate their new life in the world of One Punch Man, trying to make amends for their past deeds while also fighting new threats.
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.
In " One-punch Superman," the Weirdo King of the Weirdo Association really appeared. He was a very powerful freak with all kinds of superpowers, including invincible strength and speed, and the ability to transform at will. Together with the other monsters, he threatened the safety of the city and was eventually defeated by Saitama.