A possible plot could involve Pyrrha having to face off against other powerful characters who want to steal her Maiden powers. She would have to use her combat skills, which she's already known for, in combination with her new Maiden abilities. Maybe she teams up with some unexpected allies, like a group of outcast Huntsmen who have their own reasons for wanting to protect the Maiden powers.
One idea could be exploring the backstory of the Fall Maiden before she passed on the power. Maybe she had a secret love interest that was a threat to the order of Maidens. Another could be a story where the new Fall Maiden struggles to control her powers and has to learn from an unexpected mentor, like a character from the criminal underworld who has unique knowledge about the nature of magic.
One idea could be a story where Pyrrha and Summer are brought back to life in an alternate reality. They then have to team up to face a new, powerful threat that is endangering their world. Another plot could involve a pre - RWBY story where Pyrrha and Summer meet during a training mission and learn from each other's skills.
Perhaps Pyrrha discovers she has a connection to the MTG world. Angel, being more experienced with the MTG magic, helps her understand and control this new power within her. This could lead to a story where they travel between the RWBY world and different MTG planes, facing challenges unique to each world. They might encounter RWBY villains who are also interested in the MTG magic for their own evil purposes.
One idea could be that Pyrrha and Glynda team up to train a new group of students at Beacon Academy. They face challenges in teaching different fighting styles and personalities. Another could be a story where they go on a mission together to an ancient, magical place and have to rely on each other's skills to survive. Maybe there could be a plot where they discover a long - lost secret about the history of Remnant that only they can figure out how to deal with.
One idea could be that Ruby discovers she has the power of a Maiden in a moment of great danger. She then has to learn to control it quickly while still leading her team. Another could be that Weiss, as a Maiden, uses her ice powers in new and unexpected ways, like creating entire ice fortresses to protect her team from a powerful enemy. Maybe Blake, as a Maiden, is able to use her powers to communicate with the Grimm in some strange way, leading to a new understanding of them.
A great plot could be centered around the Summer Maiden's relationships. For example, she might have a forbidden love with a character from the other side, like a member of Salem's faction. This would create a lot of internal conflict as she has to balance her feelings with her duty as a Maiden. Or perhaps she has a deep friendship with a character who is in danger, and she has to use her powers to save them from a great threat.
One possible fanfiction could be about Ruby's journey as the Fall Maiden. She might struggle with the new power and the responsibilities that come with it. For example, she could face challenges from those who want to steal the Maiden's power for their own evil purposes. Ruby would have to learn to control the power quickly while still being true to herself and her values.
One plot idea could be Ruby struggling to hide her Faunus identity at first. Maybe she has cat ears as a Faunus and has to constantly keep them hidden under her hood. Another idea is that she discovers a unique Faunus ability that she has to learn to control. For example, she might be able to communicate with certain animals in a way no one else can.
One possible storyline could be a redemption arc for Cinder through her relationship with Pyrrha. Maybe in an alternate universe, Cinder realizes the error of her ways and Pyrrha helps her to change. They could start as enemies but gradually come to understand each other.
Her relationship with her team would likely become more complex. They might start to notice that she's different, more powerful and a bit more secretive. For example, Nora might be a bit hurt that Pyrrha doesn't share her new situation with her right away. Ren, on the other hand, would be more understanding but still concerned about the potential danger it brings to the team.