One possible plot point is that the characters start to question their own fates and destinies. Since they are watching the future, they might wonder if everything is already set in stone or if they still have the power to change things. This internal struggle could be a central theme in the fanfic. Also, the fanfic could explore how the knowledge of the future affects the military strategies against the Titans. Do they become more aggressive or more cautious? How does this new knowledge impact their training and the development of new weapons?
It could involve the characters seeing visions of a future where the Titans are finally eradicated. Maybe they see a world where humanity has rebuilt and is living in peace without the constant threat of Titans. For example, Eren might see a future where his friends are alive and happy, and this could change his actions in the present timeline.
Well, it's likely that Eren would still be one of the main characters. After all, he's a central figure in the original 'Attack on Titan' story. He might be the one most affected by seeing the future and could play a crucial role in trying to change it.
One interesting plot point could be the exploration of a character's backstory that was not fully covered in the main series. For example, perhaps we learn more about a minor character's motivation for joining the Survey Corps.
The plot could involve a conflict within the group of titan shifters because of the tenth titan. Some might see it as a threat, while others believe it's the solution to end the war. The tenth titan's power could be something that disrupts the balance between the different factions. For example, it could have the ability to nullify the powers of other titans, which would make it a highly sought - after and dangerous power.
One idea could be an OC who is a Titan Shifter with a unique ability like being able to control the elements while in Titan form. For example, they could create ice storms or fire blasts. Another could be an OC who has to struggle with the morality of being a Titan Shifter in a world where Titans are seen as pure evil. They might try to find a way to coexist with the other humans instead of just fighting Titans.
A great idea for an 'Attack on Titan' permanent titan fanfic would be to focus on the relationship between a permanent titan and a human. It could be a story of an unlikely friendship or a situation where the human is trying to study the titan to gain some sort of advantage in the fight against the other titans. The fanfic could also delve into the emotional and psychological aspects of the titan, if it has any remnants of its former human self, and how it copes with its existence.
One interesting plot point could be Spiderman trying to understand the complex politics and social structures in the Attack on Titan world. Another could be him using his scientific knowledge to find a new way to defeat the Titans. For example, he might create a special web - based formula that can immobilize them.
I think Levi could benefit as well. His combat skills are already top - notch, but seeing the future could help him anticipate enemy attacks even better. He could train his squad more effectively based on the future battles he witnesses, ensuring their survival and making them even more formidable against the Titans.
One interesting plot idea could be about a group of modern - day people suddenly finding themselves in a world similar to that of Attack on Titan. They have to quickly learn the skills of survival, like using the 3D maneuver gear which they discover in an abandoned military base. Another could be a fanfic where the Titans exist in a parallel modern world, and a secret organization has been fighting them in the shadows all along.
One idea could be exploring an alternate world where the Titans have different abilities. For example, some Titans might be able to fly or control the elements. Another plot could revolve around the characters from the original 'Attack on Titan' being transported to a completely different world with its own set of rules and threats. Maybe in this new world, the Survey Corps has to form alliances with strange new creatures to fight against a common enemy.