Sometimes, other trainers or characters from the Pokemon world might make appearances in the fanfiction. They could be friends, rivals, or mentors to Roark and Gardenia. For example, another trainer might challenge them to a double battle, or an older and more experienced trainer could give them advice on how to better train their pokemon.
In some fanfictions, there could be a story about their friendship development. Maybe they start off as rivals, with Roark being more focused on the strength of his pokemon and Gardenia on the unique abilities of hers. But as they interact more, they realize they can learn from each other. They could exchange training techniques and even help each other in pokemon battles against common enemies.
Their relationship could develop through mutual respect for their love of Pokemon. For example, James might show Gardenia some unique ways he's found to care for Pokemon during his travels, and Gardenia could teach him more about the nuances of grass - type Pokemon.
Their relationship could start with mutual respect for each other's skills with Pokemon. Ash is known for his battling prowess and Gardenia for her knowledge of Grass - type Pokemon. They might begin by exchanging tips on training and caring for Pokemon. Then, as they spend more time together, they could develop a friendship based on shared adventures. For example, going on a quest to find a rare herb that can heal sick Pokemon.
They could develop their relationship by sharing their dreams. Ash could talk about his goal of becoming a Pokemon Master, and Gardenia could share her dreams of making her gym the best in the region. By supporting each other's dreams, they form a stronger bond. For instance, Ash could help promote Gardenia's gym while Gardenia could give Ash some special training for his Pokemon.
Perhaps a plot where Gardenia has a special Pokemon that is sick, and Ash, with his experience in traveling and helping Pokemon, offers to help. They go on a quest to find a rare herb that can cure the Pokemon. Along the journey, they encounter other trainers who are also in need of help, and they have to decide whether to focus on their own mission or help others first.
Obviously, Ash is one of the main characters. Since it's about him being a legendary Pokemon in this fanfiction, he's central to the story.
Obviously, Nyssa is a main character. She is likely to be the central focus of the story, driving the plot forward with her actions and decisions. Another main character could be her first Pokemon, which she has a special bond with. This Pokemon might be her constant companion throughout her adventures.
There might be other trainers in the fanfiction. They could be friends or rivals to Elaine. A rival trainer could constantly challenge Elaine to battles, pushing her to improve. And her friends could join her on adventures and offer support when she faces difficulties.
Obviously, Sawyer is a main character. But there could also be his Pokemon as important characters. Depending on the story, other trainers he meets during his journey might also be main characters. For example, if it's a story about a big tournament, the opponents he faces could be main characters too.
Obviously, Nate is a main character. His Pokemon are also important characters in the fanfiction. Depending on the story, there might be other trainers that Nate meets during his journey, like a rival trainer who constantly challenges him.