Another interesting concept is an OC diplomat. In the complex political situation of Gundam Seed Destiny, this diplomat OC could be trying to broker peace between the Earth Alliance and ZAFT. They might have to navigate through the power struggles within each faction, facing opposition from war - hungry generals on both sides.
A third idea is an OC pilot with a special ability. Maybe they have an enhanced sense of spatial awareness, allowing them to perform maneuvers that no one else can. This OC could start as a nobody in the military but quickly rise through the ranks due to their unique skills, and along the way, they form unexpected alliances with characters from both sides of the conflict.
One idea could be creating an OC who is a skilled mechanic in the Gundam Seed Destiny universe. This OC could be involved in secretly upgrading mobile suits, adding unique features that change the tide of battles. For example, they might develop a new type of beam weapon that has less energy consumption but more power.
Imagine if the main characters from both universes swap places. Naruto finds himself in the Gundam Seed Destiny world, having to pilot a mobile suit and fight in a war he doesn't fully understand. Meanwhile, a Gundam pilot like Kira Yamato ends up in the Naruto world, having to learn about chakra and become a ninja. They both have to adapt to their new surroundings and use their unique skills to survive. This would allow for a lot of character development as they face new challenges and make new friends (or enemies) in their respective new worlds.
One idea could be a crossover with another mecha anime like Macross. The characters from Gundam Seed Destiny could find themselves in the middle of a space battle in the Macross universe, having to adapt to the different technology and combat styles. For example, they might encounter the transforming Valkyrie mechs and have to figure out how to fight against them or even team up with the Macross pilots.
One interesting concept could be alternate endings. For example, a fanfiction might explore what would happen if Kira Yamato made different choices during key battles. Another concept could be character development that was not fully explored in the original. Maybe a side character gets more depth and a new backstory in the fanfiction.
Another concept is the backstories of OCs. In Gundam Seed OC fanfiction, we often see OCs with complex pasts, like being from a colony with a unique culture that has been oppressed. Their fight in the story then becomes not just about the overarching war in Gundam Seed, but also about the liberation of their own people.
Well, you can start by creating a strong character concept for your OC. Consider their personality traits, like are they brave and impulsive or more cautious and calculating? Then, think about how they fit into the existing Gundam Seed Destiny universe. Do they side with ZAFT or the Earth Alliance? Once you have that figured out, start writing small scenes. Maybe a scene where your OC is introduced to their mobile suit for the first time. This will help you get a feel for the character and how they interact with the world around them.
One idea could be that Naruto characters possess Gundam mobile suits. For example, Naruto could pilot a Gundam with his signature orange color and use his chakra to power up the suit's special abilities. Sasuke might have a more stealth - based Gundam, using his Sharingan to enhance the suit's targeting systems.
Kira Yamato and a character from Code Geass, such as Lelouch Lamperouge. Kira is known for his strong beliefs in protecting life, and Lelouch is a master strategist with his own grand plans. They could either be at odds with each other due to their different approaches or find common ground in trying to bring peace to their respective worlds. Their meeting would surely lead to some intense debates and power struggles.
I also like 'The New Order in Gundam Seed Destiny'. This one focuses on the political restructuring after the main events of the series. It delves deep into how the different factions interact and form new alliances. The story is full of intrigue and complex relationships between the characters.
One idea could be a story where Athrun and Lunamaria are on a joint mission. They start off with some misunderstandings due to their different combat styles. But as the mission progresses, they begin to understand and respect each other more. Eventually, they form a strong bond that helps them complete the mission successfully.
Some Gundam Seed fanfictions center around the backstories of minor characters. They give more depth to those characters that we might not have seen much in the original series. For instance, a fanfiction about the pilots of the GINN suits in ZAFT. It could explore their training, their hopes, and how they view the war. And then there are fanfictions that rewrite the whole plot, starting from a different premise, like if the Coordinators and Naturals had a more peaceful coexistence from the beginning and how that would change the story.