Well, a really cool plot idea would be if the OC was sent to Middle Earth and accidentally became part of a dwarf caravan. They'd have to learn the ways of the dwarves quickly and help them on their journey, perhaps to reclaim Erebor. And then there's the idea of an OC being sent to Middle Earth as a messenger from another dimension. This OC has to find Gandalf and tell him about a coming threat that even Sauron might not be aware of, which could completely change the course of events in Middle Earth.
To create a believable OC for Middle Earth fanfiction, you need to think about the cultures and races already there. If your OC is human, what part of Middle Earth are they from? Are they from Gondor with its noble traditions or Rohan with its horse - riding culture? Their speech should also match the setting. Don't use modern slang. Their goals should be in line with the world. For instance, if they're in a time of war, they might be seeking glory or trying to protect their family. You also need to consider how they interact with the existing races. Do they fear the elves or admire them? All these aspects combined will make your OC feel like they belong in Middle Earth.
Perhaps the Dark Knights could be on a quest to find a long - lost artifact that would give them ultimate power. Along the way, they face challenges from various Middle - earth races who oppose their goal. This could lead to epic battles and unexpected alliances. For example, they might encounter elves who are protecting the location of the artifact, and a complex power struggle ensues.
One idea could be a new character from our world being magically transported to Middle Earth and having to navigate the complex politics between different kingdoms. This character could have a special ability that is unheard of in Middle Earth and that ability could either be a great advantage or a source of trouble.
Well, a plot twist could be that the girl is actually from a different time in Middle Earth's history than she thought. Maybe she was sent there not by accident but as part of a prophecy that no one in Middle Earth knew about. This could lead to her having to convince the different races, like the dwarves and hobbits, that she is there for a purpose. Also, she might be the only one who can enter a certain enchanted place because of her unique origin, and inside that place lies the secret to stopping the dark forces.
One interesting idea could be how the characters from Remnant adapt to Earth's culture. For example, they might be shocked by the variety of technology or social norms. Another idea could be the new relationships they form with Earthlings. Maybe they team up with humans to fight a common enemy that exists on Earth.
Maybe the oc is a time - traveler who has come to Earth 2 to prevent Harrison Wells from making a certain decision that will have catastrophic consequences in the future. This would lead to a lot of tense and interesting interactions between them as the oc tries to convince Wells.
A great plot idea would be a crossover with 'Game of Thrones'. The political intrigue in both worlds could be merged. Maybe Talion could find himself in the middle of the power struggle between the different houses in Westeros. He could use his skills to either side with a particular house or try to stay neutral while still achieving his own goals in Middle Earth which are now somehow intertwined with the events in Westeros.
A crossover with a modern - day setting could also be really cool. Picture Talion and Celebrimbor suddenly appearing in a big city. They would have to adapt to modern technology while also dealing with an evil force that has followed them through some sort of magical portal. The contrast between their medieval - style combat skills and the high - tech environment would make for some really interesting scenarios.
One idea could be that the little white knight discovers a hidden power within Middle Earth that can either save or destroy it. Another could be the knight forming an unlikely alliance with a group of orcs to fight a common, greater evil. Maybe the little white knight has to go on a quest to find a lost artifact that is crucial for the balance of Middle Earth.
Well, in such a fanfiction, the child can act as a sort of catalyst for change. They might bring new ideas or a different way of looking at things to the Middle - Earth. For example, they could influence the relationships between different factions in unexpected ways.