A time - travel plot would also be cool. A mecha pilot accidentally travels back in time and has to work with the predecessors of their own team. They have to find a way to get back to their own time while also ensuring that the events they change in the past don't have catastrophic consequences for the future of the Super Robot War world.
One idea could be a crossover within the Super Robot Wars universe. For example, having characters from different series team up in unexpected ways. Maybe a pilot from a mecha series that focuses on speed teams up with a more defense - oriented mecha pilot to face a new and powerful enemy that requires both their skills.
One idea could be to create an alternate universe where the mecha pilots have different personalities. For example, a usually serious pilot could be more laid - back. Another could be a story where the villains from different series in Super Robot Wars X team up for a new and unexpected threat. This would force the heroes to also form new alliances among themselves.
One idea could be that Bender and the Robot Devil get into a competition to see who can steal the most valuable items in the universe. Another could be that they team up to prank all the other robots in town. Maybe they start a robot - only casino together as well.
One idea could be a role - reversal plot. Instead of the usual power struggles between Kaguya and Miyuki, have them switch personalities for a day. It would be hilarious to see Kaguya being overly confident and forward, while Miyuki is shy and hesitant.
Another plot idea could be a war that the hounds are involved in goes awry. They might face an enemy they were not prepared for, and they have to use their unique abilities in new and unexpected ways to survive. For example, if they usually rely on speed, they might have to use their intelligence more in this new situation.
A fanfic could center around the idea that the girl they were fighting over in the movie actually has a secret identity as a spy. When they find out, they have to team up with her to take on a bigger threat, all while still dealing with their feelings for her.
One idea could be a story about an underdog kingdom rising to power through unexpected alliances. Maybe a small, resource - poor kingdom teams up with a group of powerful but outcast mages. Another could be a love story between a warrior from one warring kingdom and a noble from an enemy kingdom, which could potentially change the course of the war.
One idea could be a story about an underdog kingdom that discovers a long - forgotten magic and uses it to turn the tides of the war. Another could be a fanfic centered around the love story between a knight from one kingdom and a princess from an enemy kingdom, which then affects the course of the war. Or perhaps a tale of a young strategist who rises through the ranks and devises brilliant battle plans for his kingdom in the War of Kingdoms.
One idea could be a war between different Vocaloid factions over control of the music industry. Each faction has its own unique style and they battle it out in epic musical duels.
One idea could be exploring the backstory of a minor character in 'the darhk war'. For example, a soldier who has a hidden past that ties into the main conflict. Another could be a what - if scenario, like what if a key battle had a different outcome. It might also be interesting to focus on the relationships between different factions during the war and how they could have developed differently.