A cool plot for 'the last kingdom fanfic' might be to have a character be transported back in time to a crucial moment in the kingdom's history. They would have the knowledge of what's to come but struggle to convince others to believe them. This could lead to all sorts of interesting twists. Or you could write about a character who is secretly training a group of women to be warriors in a society that doesn't really accept that. It would be about breaking gender norms and the challenges they face in a war - torn world.
A great plot could be about a female character from 'last kingdom fanfiction' who disguises herself as a man to join the army. She then has to constantly hide her identity while also dealing with the challenges of war and her growing feelings for one of her comrades.
One idea could be that the last dragon is discovered by a young adventurer. They form an unlikely bond and together they set out to find a way to save the dragon's kind from extinction. Maybe there are ancient prophecies or hidden magic involved.
One idea could be exploring an alternate timeline where Aang fails to defeat the Fire Lord. Maybe in this timeline, the Fire Nation completely takes over the world, and the remaining benders have to go into hiding and plan a long - term resistance. Another plot could be focusing on a new airbender discovered long after Aang's time, and their journey to master airbending without the guidance Aang had.
One idea could be exploring the backstories of the characters in the 'hopeless kingdom' within the Twilight universe. Maybe a character who was once a normal human in Forks but got dragged into the chaos of the hopeless kingdom. Another could be a love triangle between a vampire, a werewolf, and a human in this new and desolate setting.
One idea could be creating an OC who is a keyblade wielder from a forgotten world. This OC could be on a quest to discover the secrets of their world's connection to the greater Kingdom Hearts universe. They might encounter classic characters like Sora and Riku and have to prove their worth as a keyblade wielder.
One idea could be exploring the lost technologies of the ancient kingdom. Maybe the characters discover a hidden vault filled with advanced weapons or energy sources that were used in the past. Another could be delving into the political structure of the ancient kingdom, like if there were different factions or noble houses that vied for power.
One idea could be a story about a new cookie character arriving in the kingdom and having to prove their worth. They could start from the bottom, make new friends among the existing cookies, and together face a new threat that the kingdom has never seen before.
One idea could be a crossover where the characters from Kingdom Hearts find themselves in the world of Blade. They could team up with the Blade warriors to fight against a common enemy, like a new form of Heartless that has emerged in the Blade universe. This would lead to interesting interactions as they learn about each other's powers and worlds.
One idea could be starting from a small, war - torn village. The protagonist, using their wits and some help from Dragon Age companions, begins to rebuild it. They focus on building defenses first, like a wooden palisade and a watchtower. Another plot could involve uniting different factions within the kingdom through diplomatic means. For example, convincing the mages and templars to work together for the greater good of the kingdom.
One idea could be an OC who is a skilled medic. They could travel between different communities in the Kingdom, facing challenges like zombie attacks and distrust from some groups while trying to save lives. This OC could also have a backstory related to the pre - apocalypse medical field, which adds depth to their character.