A common plot is Sona's struggle for power within the Devil society. In many fanfictions, she has to face off against other powerful devils while also trying to protect her own peerage. For example, in some fics, she battles against devils who want to take over her territory.
There are also fanfictions that focus on Sona's role as a student council president. She has to deal with various school - related issues while also hiding her true identity as a devil. This type of plot usually involves her using her wits to solve problems both in the human world and the devil world at the same time.
Another popular plot is Sona's relationship with Issei. Some fanfictions explore a romantic angle between them, which is quite different from the original where their relationship is more of a rivalry. These fics often show how they overcome their differences and grow closer.
I really liked a fanfiction called 'Sona's New Strategy'. It shows Sona coming up with a brilliant new plan to deal with the various threats in the 'High School DxD' world. The author does a great job of portraying Sona's intelligence and her ability to adapt. There are some really cool plot twists that keep you hooked throughout the story.
One possible fanfiction could be about Rias and Sona teaming up for a school event. They might put aside their usual competitiveness and work together to organize a devil - related festival at the school. They could combine their unique skills and powers to create an amazing event that not only impresses the other students but also strengthens their bond as friends.
One way is to explore her family background more. For example, showing how her upbringing in the devil society influenced her leadership style in the student council.
One common theme is the clash and combination of different power systems. Naruto has his chakra - based ninja powers, while the DxD universe has its own system of magic and power levels. So, seeing how these interact is a big part of it. For example, Naruto might teach Sona some ninja techniques.
A fanfiction could show how Rias and Sona first became friends. Maybe it was during a difficult time at school when they both had to face some sort of discrimination from other devils because of their different leadership styles. They found comfort in each other and decided to support one another from that moment on.
A third plot idea might be Sona trying to modernize the traditions of the devil world within the context of the school. She could face opposition from more conservative devils, and the story could explore her struggle to bring about change while still maintaining her position and respect.
Perhaps Alex Black has a mysterious past that Sona is intrigued by. They could start off as acquaintances, but as time goes on, they form a deeper bond over shared interests in magic and the supernatural world of Highschool DxD.
Power - up themes are also common. Naruto already has his powerful ninja abilities, and when combined with the magic and power systems in High School DxD, there are often scenarios where he or Sona gain new powers or find new ways to use their existing ones. For example, Naruto might learn to combine his chakra with Sona's magic for a super - attack. Another theme is friendship and alliance. Since they are from different worlds, they need to form an alliance to face common enemies. This often leads to the development of a deep friendship between them as they rely on each other's strengths.
Friendship is a common theme. Tsubaki and Sona often start with a pre - existing friendship in the fanfictions and it either deepens or is tested. For example, they might have to support each other through tough times at school or in the supernatural world.
One possibility could be that Sona's brother is a powerful figure in the underworld. He might be involved in political intrigue within the devil society. For example, he could be trying to form alliances with other noble devil families to increase the power and influence of Sona's family. Maybe he has some special abilities that are yet to be discovered by others, which he uses to his advantage in the complex power dynamics of the Highschool DxD world.