What are some interesting ideas for One Punch Man fanfiction?

A crossover with 'Dragon Ball' would be cool. Picture Saitama facing off against Goku. It would be an interesting contrast between Goku's love for a good fight and Saitama's boredom with opponents who can't challenge him.

Perhaps Si could be a new hero who has the power to absorb the powers of defeated monsters. This would make him a very controversial figure among the hero community. Some would see him as a threat, while others would recognize his potential to become one of the strongest heroes. He could also have a complex backstory related to a secret experiment that gave him this power.

One interesting idea could be exploring the backstories of the S - Class heroes in more depth. Maybe there are hidden pasts or traumas that made them who they are in the One Punch Man world. Another idea could be creating new villains that are not just powerful physically but also have complex motives and plans that pose a real threat to the heroes.

A great fanfiction idea could involve the ninjas of Naruto trying to figure out how Saitama got his incredible strength. They might study him in the hopes of creating their own super - soldiers. Another idea is a time - travel fanfic where Saitama goes back in time to the founding of the ninja villages in Naruto. And there could be a story where the One Punch Man characters get chakra and start using ninja techniques in their own battles.

One idea could be that Ben Tennyson gets the power of One Punch Man. He then has to deal with his normal alien - fighting foes but with this new overpowered ability. It would be funny to see how he adjusts to being able to defeat enemies with just one punch while still trying to use his Omnitrix in creative ways.

A cool concept for a RWBY and One Punch Man fanfiction would be a crossover tournament. Characters from both universes are invited to participate in a fighting tournament. Blake could use her speed and agility to surprise some of the One Punch Man characters, while characters like Mumen Rider could show their unwavering spirit in the face of the RWBY combatants. Also, Yang's powerful punches could be compared to Saitama's, and there could be a friendly rivalry between them over who has the stronger punch. This would lead to some interesting interactions and battles within the fanfiction.

One idea could be a yandere Genos who becomes overly possessive of Saitama. He might start interfering in Saitama's daily life, like trying to keep other heroes away from him under the guise of protecting Saitama's secret strength. Another idea is a yandere villain who falls in love with Saitama after being defeated by him and then starts stalking him, determined to make Saitama hers.

How about a crossover with 'Attack on Titan'? Saitama could find himself in the world of the Titans. His ability to defeat any enemy with one punch would be extremely useful against the Titans. He might not understand the complex politics and fear that surrounds the people in that world at first. But as he starts taking down Titans left and right, he would become a sort of legend among the survivors.

One idea could be exploring the backstory of Saitama before he became so powerful. Maybe he had a difficult training regime that involved some unique challenges. Another idea is to write a fanfiction where Genos and Saitama have to face an enemy that can nullify Saitama's power, forcing them to rely on strategy and Genos' upgrades more than ever. Also, a fanfiction about the other heroes in the One Punch Man universe forming a team without Saitama and having to deal with a powerful threat on their own could be really interesting.

One idea could be that Saitama from One Punch Man ends up in the Undertale universe. He might accidentally punch some of the monsters there, thinking they are threats like the monsters in his own world. But then he realizes that in the Undertale world, things are more complex, and not all monsters are purely bad. Another idea is a crossover where Frisk from Undertale somehow gains Saitama's power and has to navigate their own world with this newfound strength, changing the way they interact with both monsters and other characters.