Lois Lane is a must - include. She can be the love interest and also a strong - willed journalist. Jimmy Olsen is also great, providing some comical relief and being Superman's friend. Lex Luthor is an obvious choice as the main villain, always plotting against Superman.
One idea could be having Superman face an enemy that can manipulate time, causing chaos in Metropolis. Another could be a story where he has to deal with a powerful alien artifact that is affecting his powers. Maybe also a plot where he teams up with a new superhero from another planet.
Power Girl would be an interesting character for a body swap with Superman. They both have similar powers to an extent, but Power Girl has her own unique backstory and personality. The body swap could explore how their powers are both the same and different in practice. Supergirl could also be a good candidate. As Superman's cousin, she already has a connection to him. A body swap would allow for a deeper exploration of their relationship and how she could handle being in his shoes.
Superman, of course, is the most important. Then there's Lois Lane, the journalist who is always on the hunt for a story and has a special relationship with Superman. Lex Luthor is also crucial as the main antagonist.
In the 'The Adventures of Superman Novel', a significant plotline is Superman's origin story. How he came from Krypton and was raised on Earth. His discovery of his powers and how he decides to use them for the greater good. Also, his relationships with Lois Lane and other characters in Metropolis play a big part in the plotlines as he tries to balance his personal life with his superhero duties.
Obviously, Superman himself is the most important. He is the hero with superpowers. And Lois Lane is also important as she is often in the middle of the stories and has a relationship with Superman.
One main theme could be heroism. Superman is always saving the day, which shows the importance of having heroes. Another might be justice as he fights against evil to bring fairness.
To write a compelling character in Superman body swap fanfiction, first understand the essence of the original characters. If it's a human who swaps with Superman, show their initial shock and then their growing sense of responsibility with the powers. For example, they might start using the powers for small, self - centered things at first, but then realize the greater good they can do.
One interesting plot could be Superman swapping bodies with a normal human. The human then has to deal with Superman's powers while Superman experiences what it's like to be an ordinary person. He might struggle with things like paying bills or getting to work on time in the human's body.
One popular plot could be the female character who has swapped bodies with Superman trying to hide the situation from his enemies. She might struggle with using his powers in a female body, like having to adjust to the different physical strength and flying dynamics. Another plot could involve the female character exploring Superman's personal relationships while in his body and learning things about his friends and family that he hadn't shared. Also, there could be a plot where she has to quickly learn how to be Superman in order to save the day during an unexpected crisis.