Perhaps in this fanfiction, Will is the confident leader type while Gideon is more of the reserved follower. So, the story could revolve around Will leading Gideon into dangerous adventures, like exploring an ancient, haunted castle. Will's bravado and Gideon's hesitance could create interesting character dynamics.
Another plot could be that Will is a powerful sorcerer in this reverse world, and Gideon is an ordinary person who accidentally stumbles upon Will's secret. Will then has to decide whether to trust Gideon with his powers or keep him at a distance, all while Gideon is trying to prove himself worthy of Will's trust.
One idea could be that in this reverse situation, Will is the one with a mysterious power that Gideon is trying to understand. For example, Will might be able to see into other dimensions, and Gideon, being the curious character, is drawn to him to figure out how it all works.
One idea could be that they start off as rivals but then find themselves in a situation where they have to team up to solve a mystery in Gravity Falls. As they work together, they begin to understand each other better and a strange bond forms between them.
Well, perhaps they could be from different social classes in a fictional society. Gideon could be from a lower class and Eva from a higher one. Their love story then unfolds as they try to break down the barriers between their classes. They might face opposition from their families and society at large, but their love for each other gives them the strength to keep fighting. This could involve some really emotional scenes and character development as they both grow throughout the story.
In Reverse Falls Gideon x Dipper fanfiction, it's interesting because it takes two well - known characters from the original Gravity Falls and flips them in a way. The setting of Reverse Falls itself is already very different and full of mystery. Gideon's and Dipper's relationship can be explored in ways that are not possible in the normal Gravity Falls setting. For example, they could be involved in more morally ambiguous situations or have a more antagonistic - yet strangely attracted - relationship. It gives authors a lot of room to play with their personalities and create unique plotlines.
An organization that wants to control or eliminate any form of magic or special abilities could be the antagonist. Since in this fanfiction, if Will has certain powers and Gideon is involved with him, the organization would target them both to maintain their idea of a 'normal' world.
A love - interest plot for Gideon would also be interesting. He could fall in love with a character from a different realm within the Once Upon a Time universe. Their relationship would be complicated by the different rules and cultures of their respective realms. They would have to overcome many obstacles, like disapproving family members or the threat of war between their two realms.
One popular Reverse Falls Gideon x Dipper fanfiction is 'The Darker Side of Gravity'. It delves deep into their complex relationship in the Reverse Falls universe. Another good one might be 'Gideon's New Plan' which shows an interesting take on how their relationship could develop in that strange and spooky setting.
One idea could be that Reverse Dipper, who might have different characteristics in this reversed world, meets Mabel and they initially have a misunderstanding because of their different ways of thinking. Maybe Reverse Dipper is more cautious while Mabel is her usual exuberant self. They could go on an adventure where Mabel tries to teach Reverse Dipper how to have more fun and let loose.
One idea could be that Naruto accidentally uses the Reverse Harem Jutsu on himself instead of an opponent. He then has to deal with the chaos of multiple versions of himself with different personalities. For example, one might be super confident, another shy, and they all have to work together to solve a problem in the village.
One idea could be that the characters from Reverse Falls accidentally cross over into the Gravity Falls universe. They might initially be seen as threats by the Gravity Falls gang, but then they realize they have to work together to solve a mystery that threatens both universes. For example, a powerful and ancient evil that can only be defeated if they combine their unique skills and knowledge.
A Reverse Flash crossover with the Flashpoint timeline could also be great. The Reverse Flash could try to further manipulate the already - altered Flashpoint world. This could involve him trying to turn heroes into villains and vice versa, causing chaos in a world that is already on the brink of collapse.