What are some interesting plot ideas for 'Lucifer Highschool DxD Fanfiction'?

A plot idea could be Vali being sent on a secret mission by the Devils. He has to infiltrate an enemy stronghold that is rumored to be developing a weapon that could destroy the balance between the three factions. Along the way, he teams up with some unexpected allies, including some from the Angel faction who also don't want the balance to be disrupted.

One idea could be that Lucifer has a secret mission on Earth related to the events in Highschool DxD. He could be observing the main characters to see how they are handling the supernatural situations, and perhaps he has a greater plan in store for them. Maybe he's looking for a new heir or a special power that could be hidden among the students.

A plot could involve the main characters having to form an alliance with Trihexa to face an even greater threat. They would have to find a way to communicate and work with it, which would be a huge challenge considering its nature. This could lead to some interesting character development, especially for Issei as he tries to understand and tame Trihexa.

Well, a plot could revolve around a mystery that involves both worlds. Maybe there is an ancient artifact that has the power to disrupt the balance between the Naruto universe and the Highschool DxD universe. Characters from both sides have to work together to find and protect this artifact. This would lead to a lot of character development as they learn about each other's cultures and values while on this quest.

One idea could be a new character joining the school who has a unique supernatural ability that no one has seen before. This could disrupt the existing power dynamics and create all sorts of interesting interactions and challenges.

A plot could also focus on a new character who is a hybrid of the two universes. They have the powers of both a devil from High School DxD and a wizard from Harry Potter. They struggle to find their place in either world as they are too different from the norm in both, and they embark on a journey to create their own identity and purpose.

A plot could involve a nekoshou trying to fit into the high school environment while hiding their true nature from most students. But then they get involved in a magical tournament where they have to use their nekoshou abilities to win and prove themselves. Or perhaps a nekoshou is on a quest to find a lost nekoshou artifact that has a connection to their family's past in the Highschool DxD universe.

One idea could be Sora being a new exchange student at the school in the Highschool DxD universe. He could bring with him unique powers or knowledge that intrigue the main characters. For example, he might have a special type of magic that is different from what is commonly known in their world.

One idea could be an alien race coming to Kuoh Academy with unique powers that the devils, angels and fallen angels have to deal with. For example, an alien race that can manipulate time, causing chaos in battles and daily life.

One idea could be a new devil character arriving at Kuoh Academy with a unique power that challenges the existing power dynamics among the devils there. For example, a devil who can manipulate time in small increments during battles, which would make for some really intense and strategic fight scenes.