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 of the great 'Evil Superman' stories is 'Injustice: Gods Among Us'. In this story, the Joker tricks Superman into killing Lois Lane and their unborn child, which drives Superman over the edge. He then begins to enforce his own brand of justice in a very extreme way. Another is 'Red Son', where Superman is raised in the Soviet Union and his values are shaped by a different ideology, leading to a very different take on the character. And 'The Dark Knight Returns' also has an interesting take on a Superman who is more of a tool of the government and not the pure hero we're used to.
Yes, there have been storylines where Superman has been depicted as going against his usual heroic nature and turning evil, but it's not a common or permanent occurrence.
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.
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.
Often, there could be other superheroes or villains. For instance, Lex Luthor might make an appearance. He could either be an ally to the reader in trying to stop the evil Superman or have his own ulterior motives for getting involved. Another character could be Lois Lane. She might be used as a plot device, perhaps the reader has to protect her from the evil Superman or she could be a source of jealousy for the evil Superman if he has feelings for the reader.
No. Superman comics are mainly about his heroic deeds, saving the world, and his battles against villains. They don't contain erotic stories as it goes against the positive and family - friendly image of Superman.