One idea could be exploring the backstories of the individual witches more in - depth. For example, how they first discovered their powers and what their lives were like before joining the fight. Another could be a story about a special mission that the witches have to undertake behind enemy lines, filled with danger and unexpected alliances.
A plot could center around a new witch joining the group during World War 2. She could struggle to fit in at first, having different ways of using her powers compared to the others. As the story progresses, she overcomes her differences and becomes an integral part of the team. This could also show the dynamics within the group and how they adapt to new members.
Perhaps a fanfiction could be written about the witches' interaction with regular military forces. How they are perceived by the soldiers, and the challenges they face in terms of cooperation. It could also involve a situation where the witches' abilities are not fully understood by the military brass, leading to some tense moments and the need for the witches to prove their worth.
One idea could be that the Spartans from Halo and the Witches from Strike Witches team up to fight a common alien threat that has invaded both of their universes. The Spartans' advanced weaponry and combat skills combined with the Witches' magical abilities would make for an epic battle.
Sanya V. Litvyak is often a popular character. Her calm and collected nature, along with her powerful abilities, make her interesting to write about. Fans like to explore her backstory, especially her time in her homeland before coming to fight in the war.
Another interesting plot point is the mystery behind the Neuroi. Their origin and motives keep readers intrigued. The light novel may explore different theories about them, like whether they are just mindless invaders or if there is a greater purpose behind their attacks. This adds an element of mystery and suspense to the overall story.
Maybe the witches kidnapped the character because they believe the character is the key to a prophecy. The character could then try to find out more about this prophecy and use it to their advantage, like befriending some of the nicer witches to help them escape. This could involve a lot of exploration within the witches' lair, finding hidden passages and ancient scrolls that hold the secrets of the prophecy.
A great plot for Strike the Blood fanfiction could be a time - travel scenario. Kojou is sent back in time to a period when vampires were first emerging. He has to use his modern - day knowledge and powers to survive in this ancient and dangerous time, while also trying to find a way back to his own time. This would allow for a lot of world - building and exploration of the vampire lore in the series.
Maybe the boy is a descendant of an ancient witch hunter, but he doesn't know it. When he meets the witches, they initially think he's a threat. However, as they get to know him better, they realize he has no intention of harming them and they all team up to fight a common evil that is emerging in their town. For example, a dark force that is draining the magic from the witches and causing strange happenings in the area.
One idea could be an OC who is a powerful vampire hunter sent to the island where the story takes place. They initially clash with the main characters but end up teaming up to face a greater threat. For example, a new type of ancient vampire that is immune to the usual methods of slaying.
One idea could be exploring the rebuilding efforts on Earth. Show how different cities are being reconstructed and the role of various superheroes in it. For example, Iron Man could be using his tech to rebuild Stark Tower.
One idea could be exploring the backstory of a minor character in more depth. For example, the character of Marthe. We could see her life before she came to serve the de Clermont family. Another plot could involve a different magical creature being introduced into the world of the story, like a phoenix, and how it interacts with the witches, vampires, and daemons. Maybe it could be a key to solving some of the ongoing mysteries in the 'A Discovery of Witches' universe.
One interesting plot could be about the coven of witches helping Harry Potter in a new and unexpected way during his fight against Voldemort. Maybe they use their unique magic to create a powerful shield around Hogwarts.