Imagine the OC has the power to sense emotions. She can tell that Pietro is hiding some deep - seated pain or fear beneath his confident exterior. She tries to reach out to him, but he initially resists. As the story progresses, he slowly opens up to her, and they develop a strong emotional connection that might turn into love.
The OC could be a mutant from a different country who comes to the X - Men school. Pietro is immediately intrigued by her different culture and way of using her powers. They start to exchange stories about their mutant experiences, and a relationship forms based on mutual understanding and respect for their differences.
One plot idea could be Pietro and Wanda exploring their powers further in a world that fears them. They might have to team up with other X - Men to face a new, powerful mutant - hating organization. Another could be a story set in an alternate universe where they have different relationships with the other mutants. For example, Pietro could be more of a loner and Wanda has to convince him to work with the team.
One plot idea could be that the OC is a new mutant at the school and Kurt is assigned to show them around. They start off as friends but gradually develop deeper feelings as they face challenges together, like dealing with a bully mutant. Another could be the OC has a special power that Kurt needs to help control, and in the process, they bond over their shared experiences of being different.
One idea could be an OC with a unique power that attracts the attention of multiple X - Men characters, leading to a harem - like situation. For example, an OC who can manipulate time on a small scale. This power could be both useful and dangerous, and different X - Men might have different reactions to it, some being intrigued and others being cautious.
One idea could be creating an OC with a unique mutation that has never been seen before in the X - Men universe. For example, the ability to manipulate time on a small scale, like slowing down or speeding up time in a limited area. This OC could be a new student at the Xavier Institute and face challenges in controlling their power while also trying to fit in with the other mutants.
One idea could be inserting yourself as a new mutant with a unique power that the X - Men initially suspect but then come to trust. For example, a power to manipulate time on a small scale, which could be used to save the team from a sudden ambush.
A plot idea could be that Bobby and Jubilee get trapped in a time - loop. Each time they relive the day, they notice different things about each other and their powers. At first, they're frustrated, but as they work together to break the loop, they develop a deeper understanding of one another.
In some fanfictions, the OC could have a power that is the opposite of Pietro's in some way. For example, if Pietro is all about speed, the OC could have a power related to slowness or time - stopping. This contrast would create interesting dynamics. They might start off as rivals, constantly challenging each other. But then, they realize that together they can be a great team, like two sides of a coin. Eventually, their relationship could evolve into something deeper as they learn to complement each other.
You could do a crossover with the Inhumans. The X Men and Inhumans have some similarities in terms of having special abilities. In the fanfiction, there could be a misunderstanding at first between the two groups. For example, Beast could be fascinated by the Inhuman biology while some of the more hot - headed X Men like Gambit might be a bit more aggressive in their initial interactions. Then they would have to work together to face a threat like an alien invasion.
One idea could be an OC who has the power to manipulate time like Pietro. They could team up with Pietro to save the Avengers from a time - trapped enemy. The OC might be from a different dimension where time works differently, adding an interesting dynamic.
Maybe an OC who has the power of telepathy but in a very unique way. Instead of just reading minds, they can project their thoughts into the dreams of others. This OC could be used to either help the X - Men by warning them of threats through their dreams or be a villain who uses it to plant false ideas in their heads. They could have a complex backstory about how they developed this power and why they choose to use it in the way they do.