An interesting plot could involve an OC who was initially an enemy, believing the Gekirangers were a threat to their own goals. But as the story progresses, they discover they have a common enemy. The OC then has to learn to work with the Gekirangers, overcoming their differences and prejudices. This would create a lot of character development and interesting interactions between the OC and the existing characters.
One common theme is power - how an OC's power interacts with Rio's. For example, in some fanfics, the OC has a power that complements Rio's fighting style.
Give your character a distinct personality trait. For example, if your OC is always overly optimistic in the face of danger, it can make them stand out. They could be cracking jokes during battles or always seeing the good in every situation, which would be different from the more serious characters in the series.
One interesting concept could be unique power-ups for the original characters (OCs). For example, an OC might have a power-up based on a mythical creature from local folklore that adds a new dimension to the battles. Another concept could be the relationships between OCs and the existing Super Sentai members. They could start as rivals but gradually become allies, creating complex and engaging story arcs.
One popular 'Super Sentai Gekiranger Rio' OC fanfic is 'Rio's New Adventure'. It explores Rio in a new storyline where he teams up with an OC. Another one could be 'The Secret of Rio', which delves deeper into his past and relationships with the help of original characters.
Well, there could be a story where the Super Sentai are on a mission and end up in a parallel universe that is a blend of Disney and their own world. They meet characters like Aladdin and his magic carpet. The Sentai could use the carpet to travel quickly across different locations in this new world while they search for a way back home. At the same time, they notice that some dark force is corrupting the beauty of this Disney - Sentai world. So, they join forces with the Disney heroes like Hercules to fight against this dark force and restore the balance in the world.
One idea could be that the heroes from MHA are transported to the Super Sentai world and have to team up with the Sentai warriors to fight a common enemy that is threatening both universes. Maybe a powerful villain has found a way to cross dimensions and is causing chaos.
One idea could be a crossover where the heroes from My Hero Academia team up with the Super Sentai. They could face a common enemy that has powers combining the quirks from the MHA world and the mecha - like threats from Super Sentai. For example, a villain who can create quirk - enhanced giant robots.
A cool plot could involve a villain who has the ability to steal the memories of the heroes. The Power Rangers and Super Sentai teams then have to work together to regain their memories while also fighting off the villain's minions. They could start with just basic combat skills and gradually remember their more powerful abilities as the story progresses.
One common theme is self - discovery. The OCs often start out not fully understanding their powers or place in the Super Sentai world, and then gradually figure it out. For example, in many stories, the OC discovers a hidden ability that changes their role in the team.
Well, in super sentai fanfic, power - up concepts are quite popular. Writers often come up with new and exciting ways for the sentai members to gain stronger powers. Then there's the theme of backstories. Fans are interested in delving deeper into the pasts of their favorite characters, so many fanfics focus on creating detailed backstories for them. Also, redemption arcs for villains can be a common theme, where the bad guys get a chance to turn good in these fan - created stories.