Mercy Graves is an underrated character. In a fanfic, she could be developed more as a complex character. Maybe she has her own motives for being involved in Lex Luthor's schemes. She could be the one who has a change of heart and tries to stop Luthor from pitting Batman and Superman against each other, adding a new layer of intrigue to the story.
Mr. Harrison, the rather grumpy neighbor. He could be explored more deeply. There could be a backstory about why he's so grumpy and how Anne's presence gradually changes his outlook on life. It would be interesting to see his softer side and how he interacts with the community in a different way.
Batman and Superman are obviously very popular. They are the main focus of the original movie, so in fanfiction, they often take center stage. Writers love to explore their complex relationship, whether it's a friendship, rivalry, or a combination of both.
The Genovian citizens. In fanfiction, individual citizens could be highlighted. For instance, a young Genovian girl who looks up to Mia as a role model. We could follow her journey of trying to be like Mia, and through her eyes, we can see how Mia's actions as princess impact the people of Genovia on a more personal level.
One underrated character is Prentiss. He's often just in the background in the original, but in fanfiction, he could be the hero. Maybe he discovers a hidden power within himself that helps Peter and the gang. Another is Ted. He could be given more spotlight by having his own backstory explored, like how he ended up on the ship in the first place.
Padma Patil. In the original story, she's sort of in the background. But in a fanfic, she could be a really interesting character. Maybe she has some secret knowledge about the Triwizard Tournament or a special connection to one of the visiting schools. She could play a crucial role in helping Harry or another character navigate the challenges of the tournament.
Pony Head is a character that could be explored more. In fanfic, she could have a backstory about how she became so self - centered and what really happened to her family. It would add depth to her character.
Xenovia is another underrated character. In future fanfiction, she could play a much bigger role. For instance, she could be the one to discover a new holy sword that has the power to not only slay devils but also has some sort of purification ability that could change the balance between the factions. She could also have a more complex relationship with Issei, not just as a friend or ally but with some romantic undertones.
Rock Lee. He has such a great determination and unique fighting style. In fanfiction, we could explore his journey to become an even greater ninja, perhaps by giving him some new techniques or having him face opponents that really test his limits.
The character of [character name]. In the original trilogy, they were kind of in the background, but in fanfiction, they could be shown to have hidden powers or a really interesting personality. They could be the key to solving a big mystery that the main characters are facing.
Batman is quite interesting. His determination to take on Superman, despite the obvious power imbalance, shows his tenacity. And Superman himself is also interesting, as he struggles with being both a hero and an object of fear. Wonder Woman is another, with her mysterious past and her own motives for getting involved.