Female Genos could be developed with a more empathetic side. Since she is a cyborg, she could struggle with understanding human emotions more deeply. Maybe she starts to learn about love and friendship in a different way compared to male Genos. For example, she might be more sensitive to the feelings of other female characters around her.
First, consider the role the OC will play. If it's a partner for Genos, think about their combat abilities. For example, if Genos is mainly a physical fighter, the OC could be a support with long - range attacks or healing powers.
You can start by looking on fanfiction - dedicated websites such as Archive of Our Own (AO3). It has a large collection of fan - created works, and you can simply search for 'female Genos fanfiction' in the search bar. There are likely to be various stories there.
There are fanfictions where female Genos is placed in alternate universes. For example, in a steampunk - inspired universe, she could be a mechanic with enhanced robotic parts, fighting against different kinds of villains. These stories often play with the concept of her character in a new and exciting setting.
One common theme is the exploration of an unlikely relationship. Since Saitama is very powerful and Genos is his disciple, in a female Genos x Saitama scenario, it often involves how they navigate their feelings while maintaining their roles in the hero - disciple dynamic.
To write a Genos crossover fanfiction, think about the differences and similarities between Genos' world and the other universe. For example, if it's a crossover with a magical world, how will Genos' technology interact with magic? Develop your characters well, not just Genos but also the characters from the other universe. Make sure their interactions are believable. You can also add some humor or drama to make the story more engaging. Maybe Genos tries to learn magic but keeps failing in a comical way. This can add a light - hearted touch to the story.
How about Alucard from Hellsing? He is an extremely powerful immortal. In a crossover with Genos, Alucard's centuries - old experiences and his complex relationship with humanity could play off well against Genos' more recent creation as a cyborg. They might start off as adversaries, but then find common ground in their fight against a greater evil. Genos could learn a lot about the nature of immortality from Alucard, who has seen so much over the years.
Their relationship could develop through shared experiences. For example, they could be on a mission together to save a city from a monster. During this, they face difficulties and rely on each other's strengths. Saitama's raw power and Genos' technological abilities combine well. This mutual dependence can be the first step in building a deeper connection.
One plot idea could be that Female Genos is in a battle and gets severely damaged. Saitama helps her repair and during this process, they start to understand each other on a deeper level. They might share their pasts, like Saitama talking about his mundane pre - hero life and Genos about her reasons for becoming a cyborg. This could lead to a budding friendship or something more romantic over time.