His hair could also be a plot device in a more comical way. Imagine a situation where his hair has a mind of its own and keeps getting him into embarrassing situations. Like it gets stuck in a door right before a big fight, and he has to struggle to free it while the villain is making fun of him.
One idea could be a fanfiction where Saitama's hair suddenly gains sentience. It starts to give Saitama advice on how to be more heroic in a sassy way. For example, it might tell him to change his plain hero costume to something more flashy to attract more fans.
One idea could be that Saitama's hair gives him some new, unexpected power. For example, his hair could start to glow and act as a power amplifier, allowing him to defeat enemies even more easily than before. This would be a fun twist on his already overpowered character.
Well, a lot of One Punch Man fanfictions about heroes seeing Saitama are really interesting. Some focus on their initial shock at his power. For example, Genos is always in awe of Saitama's strength in the original work, and in fanfictions, this can be explored even deeper, like how he tries to understand the source of that power.
If Saitama became a monster in fanfiction, his physical appearance would surely change drastically. His bald head, which is now a symbol of his simplicity and power, might take on a more menacing look. His eyes could turn red, and his muscles might bulge in an even more grotesque way. This transformation could also affect his relationships. Genos, for example, would be in a difficult position. He idolizes Saitama as his master, but if Saitama becomes a monster, Genos might have to fight him to protect the city.
One way is to explore his life before he became a hero. Maybe he had a normal job and was constantly frustrated with the mundanity of it. This could have been the catalyst for his intense training.
A plot where Saitama travels to different dimensions in the One Punch Man universe. He could encounter strange versions of himself or other heroes and villains, leading to humorous and action - packed situations.
First, understand the characters well. Saitama is bored with his power and just wants a good fight, while Boros is a proud and powerful alien seeking a worthy opponent. Then, come up with a unique plot. Don't just rehash their fight from the original. Maybe create a new world or situation for them. For example, a world where all heroes have lost their powers and Saitama and Boros have to work together to save the day. Also, good dialogue is key. Make it sound like how the characters would actually talk. Saitama's simple and straightforward speech and Boros' more grandiose way of speaking.
A character could be a hair - stylist in the One Punch Man universe who is obsessed with getting to style Saitama's hair. He or she could follow Saitama around, much to his annoyance, offering different hair - styling ideas and thinking that it would enhance Saitama's already overpowered status.
One common theme is the exploration of Saitama's power in different universes. For example, when he crosses over to a universe with magic, how his physical strength compares to magical abilities.