Identity exploration is also a theme. The sister might be struggling with being in Saitama's shadow or trying to find her own identity as a hero or just as an individual. She could be trying to make a name for herself without relying on her brother's fame.
One good fanfiction could be 'Saitama's Sister: The Hidden Power'. It explores the idea of Saitama having a sister with her own set of powers. In this story, she tries to keep up with her brother's reputation while also finding her own place in the hero world.
Saitama's true strength was recognized by many in One Punch Superman. With the help of his neighbor and teacher, Dr. Orochi, people gradually understood his strength. Dr. Orochi had once told Saitama that he had powers beyond that of a human, and that he could strengthen himself through training. In addition, Saitama's teacher, Hungry Wolf, also called him the " strongest human." In addition, other characters such as Superman and Atom also acknowledged Saitama's strength.
One possible plot could be that Tornado initially challenges Saitama out of pride. She sees his nonchalant attitude and wants to prove that her psychic powers are superior. Saitama, being Saitama, just goes along with it. As the battle unfolds, Tornado throws everything she has at Saitama, but he just dodges casually. Eventually, Saitama throws a light punch that knocks Tornado back, but not seriously hurt, which makes her realize his true strength.
To write a character - driven story about Saitama, focus on his boredom. Show how his extreme power has made his life lackluster. For example, you could write about his attempts to find a hobby that actually challenges him. Maybe he tries painting, but he's so good at it immediately that he gets bored. This exploration of his search for something to fill the void in his life can be a great character - driven story.
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.
In a fanfiction scenario between Tornado and Saitama, Saitama would likely win. He's so overpowered that he can defeat any opponent with one punch. Tornado is extremely strong with her psychic powers, but Saitama's strength seems limitless. His simple training routine has made him so powerful that no enemy has been able to withstand his punch so far.
I think Saitama is stronger. His power is seemingly limitless and he has never struggled in a fight. Goku, although powerful, has had many intense battles where he was pushed to his limits.
There was no conclusive evidence to prove that there was a god living in Saitama's body. In the story of One Punch Superman, Saitama was a character with superpowers. His abilities came from his strong body and combat experience. Although he had shown supernatural powers in some plots, such as being able to emit powerful light or changing the weather, these powers were all fictional and not real superpowers. Therefore, there was no conclusive evidence that a god lived in Saitama's body.