One idea could be Saitama and Tatsumaki teaming up to face a new, extremely powerful villain that even Saitama has trouble with at first. Maybe this villain has the ability to manipulate reality in a way that nullifies Saitama's strength for a short time, and Tatsumaki has to use her psychic powers to protect Saitama while he figures out a way to overcome this new obstacle.
A plot could revolve around Tatsumaki developing feelings for Saitama. She is initially in denial about it because of Saitama's unassuming appearance and his 'boring' hero lifestyle. However, as they go on more missions together, she starts to see his true heroism and selfless nature, which gradually makes her fall for him. This could lead to a lot of comical and heartwarming moments between the two.
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.
One possible plot idea could be that Tatsumaki gets injured during a battle and Saitama has to take care of her. This would force them to interact closely and start to understand each other better. Another idea is that they are both chosen for a special mission together. Along the way, they face various challenges that require their combined powers. Tatsumaki might initially be dismissive of Saitama, but as they work together, she realizes his true strength and value. This could lead to the development of a deeper relationship between them.
A cool plot might be a time - travel fanfiction. Saitama travels back in time to when he was just starting to become strong. He meets his past self and tries to guide him, but also has to deal with monsters from that era who are now different threats due to the time shift. And there could be a mystery element where Saitama has to figure out why time is acting strangely in the first place.
One idea could be Saitama facing an enemy that can copy his strength but not his speed. This would create a unique dynamic as Saitama has to use his wits more than just his punch. Another plot could involve Saitama traveling to a different dimension where his power is nullified and he has to start from scratch to regain his strength. And perhaps a plot where Saitama has to train a new hero who is having trouble controlling their own power, similar to how he was once a regular person trying to become strong.
One idea could be that Evil Saitama is actually a clone created by a mad scientist. The clone has all of Saitama's power but none of his morality. He starts to create chaos in the hero world, challenging heroes and causing destruction. Another plot could be that Evil Saitama is an alternate version from a parallel universe where he turned bad due to a tragic event in his past. He then travels to the main One Punch Man universe to seek revenge on the heroes there.
One popular plotline is Tatsumaki trying to get Saitama to take things more seriously in battle. Since Saitama is so overpowered, Tatsumaki, with her strong sense of pride in her own abilities, might feel frustrated by Saitama's nonchalant attitude. Another plotline could be a team - up against a powerful new villain. The contrast between Saitama's simple yet extreme strength and Tatsumaki's more complex psychic powers would make for an interesting dynamic in combat.
One idea could be that Saitama and Tatsumaki are forced to team up for a special mission. During this mission, Tatsumaki starts to see Saitama's hidden strength and unique charm, which gradually changes her initial dismissive attitude towards him.
A fanfiction plot could involve Tatsumaki and Saitama getting trapped in an alternate dimension. They have to rely on each other to find a way out. Along the way, they learn more about each other's pasts and what made them become heroes. This would be a great opportunity for character development and exploring their relationship in a new setting.
There could be a story where they both participate in a hero - training exercise together. At first, Tatsumaki tries to show off her powers and outdo Saitama. But Saitama doesn't really care about competing. As the exercise goes on, they face unexpected challenges that require them to rely on each other's unique abilities. This could be a great opportunity for their relationship to grow, whether it's a friendly bond or a romantic one.
Definitely not. One Punch Man is a manga that focuses on action and comedy, not on presenting nude characters. The creators aim to entertain through the story and characters' abilities, not through inappropriate imagery.