There could be many interesting aspects in a female Nidus fanfiction. Maybe it could explore her origin story. Since Nidus is a unique and somewhat grotesque yet fascinating Warframe, a female version might have a different backstory related to the Infestation. For example, she could have been a female Orokin scientist who was accidentally infected and instead of succumbing to it, she learned to control the Infestation in a way that no one else could, leading to her becoming the female Nidus.
One possible plotline could be that the female Nidus is on a quest to find a cure for the Infestation. She believes that there is a way to reverse the process that turned her into what she is. Along the way, she has to face off against other Warframes who fear her and the power she wields. Another plotline could be her being hunted by the Corpus or the Grineer who want to use her unique abilities for their own evil purposes.
The fanfic could be set in a post - war scenario. Nidus and Saryn are part of a group trying to rebuild the war - torn areas of the Origin System. Nidus is using his powers to purify and transform the infested areas into something more habitable, while Saryn is using her toxins to destroy any remaining harmful substances. At first, the other members of the group are a bit wary of their powers. But Nidus and Saryn prove their worth. They also start to develop a special connection as they work side by side, with Nidus being intrigued by Saryn's scientific approach to her powers and Saryn being fascinated by Nidus's biological mutations.
To write a great Warframe Nidus x Saryn fanfic, start with a strong opening. Maybe describe a battle scene where they first meet in the middle of chaos. Then, develop their relationship gradually. Have them exchange banter about their different ways of fighting. For example, Nidus could tease Saryn about her 'slow - spreading' toxins compared to his fast - acting infestation. In terms of setting, use the rich lore of Warframe. You could set it in the Void, where strange things happen to their powers. Also, don't forget about the other characters in the Warframe universe. Maybe they have to interact with Teshin or the Lotus at some point, which adds more depth to the story.
A good female nidus fanfiction could be centered around her relationship with other characters in the original story's universe. For instance, how she interacts with a mentor figure and how that relationship helps her grow. It could explore her emotions and development in a more in - depth way compared to the original work.
Begin by imagining a scenario for the female nidus. It could be something as simple as her having a normal day that suddenly takes a strange turn. Then, build on that by creating conflicts and resolutions. You also need to consider her personality traits and how they would influence her actions in the story.
Writing or seeking fanfiction with sexual content is inappropriate and often violates the terms of use of most platforms. So, I cannot support or promote such content.
One interesting story could be about an operator who forms a deep bond with their Warframe during a difficult mission. The operator discovers new abilities of the Warframe that were previously unknown, and together they overcome a powerful enemy. For example, the operator might find that their Rhino Warframe can perform a special charge move in a particular situation that saves them from a horde of enemies.
One idea could be a story where Nidus and Stalker team up to face a common enemy. They could start off as reluctant allies, gradually learning to trust and respect each other's skills.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are a lot of Warframe - related fanfictions there. Just use the search terms 'warframe operator x warframe' and you'll get a bunch of results. Another place could be the official Warframe forums. Sometimes fans post their stories there as well.