A really cool Attila Fate fanfic could be centered around a time - travel plot. Attila gets sent to a different era in the Fate universe, perhaps a more peaceful time, and has to adapt. This could lead to interesting character development as he grapples with the differences in values and ways of life. It could also create some unique interactions with the characters native to that era, and explore how his presence affects the overall balance of that time period.
Well, you could write a fanfic about Attila's relationships. For example, how he forms alliances or rivalries with different heroes or villains in the Fate world. You might also consider a story where Attila discovers a new power or ability and how that changes his role and interactions within the Fate storyline.
Another interesting concept is to create an alternate ending. Maybe the two factions end up working together against a greater threat that was hidden all along, like an ancient evil that awakens during their battle.
A great plot for a Fate Tiamat fanfic could be a scenario where Tiamat tries to adapt to the modern world within the Fate universe. She has to deal with human culture, technology, and the other strange things she never encountered before. This could lead to some comical as well as deep and meaningful interactions with the other characters.
There could be a fanfic storyline where a city under siege manages to survive against all odds. The defenders use innovative tactics such as creating traps within the city walls, using the terrain to their advantage, and even launching surprise counter - attacks. Also, a story about a group of mercenaries who side with different factions throughout the game based on the highest bidder, but eventually find loyalty in one particular faction after experiencing its just rule and noble leadership.
Well, you could focus on the concept of fate itself within the 'fate in time fanfic'. How about a story where the characters are aware of their fates but struggle against them? They could try to rewrite their destinies, which would lead to all sorts of interesting conflicts. Or perhaps a plot where fate is a sentient force that plays games with the characters, constantly changing the rules of time.
A good plot for a Brynhildr Fate fanfic could be a time - travel story. Brynhildr could be sent back in time to a crucial moment in her own history. She could then have the chance to change things that she regretted in her past. Or, you could write about Brynhildr falling in love with a character who is not from her original story. This would create a lot of interesting drama as she tries to balance her new feelings with her duties as a Servant. Also, a story where Brynhildr has to train a new and inexperienced Servant could be quite engaging.
Another idea is to create a story where the rules of the Grail War are changed. For instance, instead of seven Servants, there are only three, and they have to complete different tasks to win. This would completely change the dynamics of the story and lead to new and exciting interactions between the characters.
One idea could be to explore an alternate timeline where the main characters make different choices at a crucial moment. For example, if a character who usually chooses to fight decides to negotiate instead, how would that change the course of the story? Another plot could involve a new character being introduced who has a special power that disrupts the existing power balance in the 'game of fate' world. This new character could either be a force for good or evil, depending on their motives.
One idea could be exploring Arjuna's relationship with other Servants in a modern-day setting. For example, how he adapts to living among them and dealing with modern technology.
Another interesting plot could be a time - travel scenario within the 'breach of fate' world. A character goes back in time to try and prevent a certain 'breach' from happening, but in doing so, they create unforeseen consequences that make the situation even more complex.
One idea could be exploring how small, chaotic events in a character's past in a fate - based story drastically change their future. For example, a single missed encounter due to a chaotic traffic jam might lead a character on a completely different path of destiny.