Gohan may become more confident in relationships. In a harem situation, he has to deal with multiple people interested in him, which could boost his self - assurance.
In a Broly x Gohan fanfiction, Gohan could develop a new understanding of power. Instead of just relying on his academic knowledge and some of his traditional training, he could learn from Broly that power can also be about pure instinct. Meanwhile, Broly could develop his mental faculties. Gohan might introduce Broly to things like meditation or mental focus exercises. As a result, Broly becomes less of a mindless brute when it comes to fighting and more of a thinking fighter, which would be a significant character development for him.
Well, it could be a powerful gamer who has a grudge against Gohan. Maybe this gamer has lost to Gohan in some important in - game tournaments and now wants revenge. So he devises all kinds of devious plans to undermine Gohan's progress in the game.
For Gohan, you could start by showing his growth from his previous experiences. Maybe he's more confident now and is taking on a leadership role. He could be mentoring Trunks in certain aspects. For Trunks, show his eagerness to learn from Gohan and his own journey of becoming stronger. He might start out a bit impulsive and learn to be more calculated as he spends time with Gohan.
Another aspect of his development in fanfiction is his relationship with his family. In some stories, he might reconcile with his father, Goku, or his mother, Chi - Chi. This can be a major turning point in his character arc, as it can bring out the more human and emotional side of Dark Gohan that was perhaps overshadowed by his darkness before.
Obviously, Gohan is the main character. But often, you'll also see characters like Piccolo. Piccolo might be a mentor - like figure, giving Gohan advice on how to handle his new dragon master powers.
While Naruto and Gohan are the central focus, the fanfic could also introduce new characters created specifically for this story. These new characters could be neighbors or someone who is affected by the presence of Naruto and Gohan living together, which would then drive the plot forward in new and unexpected ways.
Well, clearly Gohan and Baby Pan are the main characters. Gohan, being an experienced fighter and Son Goku's son, brings his strength and knowledge. Baby Pan, on the other hand, is full of potential and innocence, which makes her an interesting character to explore in the fanfiction.
In addition to Gohan and Issei, Rias could be a main character in this fanfiction. She is a powerful devil and a key figure in the Highschool DxD universe. Her relationship with Gohan could be complex, especially when it comes to power dynamics and her own goals for her peerage. She might be intrigued by Gohan's power and want to recruit him or at least form an alliance with him.
Future Gohan's character development would likely involve him becoming more resolute and determined. After all the hardships he's faced, he would grow stronger both physically and mentally. He might start as a somewhat broken hero, but as the story progresses, he'd regain his confidence and find new purpose in protecting what's left of his world.