Perhaps an OC that is a powerful sorcerer but has been in hiding. In the fanfiction, they are drawn out of hiding by the events in 'Legend of the Seeker'. Their goals might be different from the main characters. They could be seeking to regain lost magic artifacts while the main characters are focused on the Sword of Truth.
One idea could be creating an OC who has a unique power related to nature in the world of 'Legend of the Seeker'. For example, the ability to communicate with animals. This OC could then get involved in the main quests, either helping or hindering the main characters depending on their motives.
An interesting plot could revolve around an OC who is from a long - lost tribe in the 'Legend of the Seeker' universe. This OC might hold the key to an ancient prophecy that the main characters are trying to understand. They could bring new knowledge and different cultural elements to the story.
One idea could be creating an OC who is a long - lost relative of one of the main characters. For example, a cousin of Richard who has been living in a hidden village and has unique magical abilities that are different from what we've seen in the show. Another idea is an OC who is a traveling bard that records the adventures of Richard and Kahlan, but secretly has a prophecy - related mission of their own. A third idea could be an OC who was once an enemy but then gets redeemed through a series of events and becomes an important ally in the fight against the dark forces.
One idea could be an OC (Original Character) who is a long - lost relative of Spyro. This OC could have unique powers that complement Spyro's. For example, while Spyro has his fire - breathing ability, the OC could have the power to control ice. Their journey could involve them teaming up to face a new, powerful enemy that neither could defeat alone.
One interesting story could be about the main characters having to face a new and more powerful dark magic threat that wasn't in the original series. It could show their growth and new strategies to overcome it.
An interesting Legend of Korra OC fanfiction idea could involve an OC who was born with the ability to control spirits directly, without the need for Avatar - like mediation. This OC could face challenges as people fear their power. Also, an OC that is a bender who has lost their bending due to some accident and has to find a new way to be useful in the world of bending. Maybe they become a great teacher, teaching non - benders how to defend themselves against benders. And then there could be an OC who is a descendant of an ancient civilization and has access to forgotten bending knowledge.
One idea could be creating an OC who is a lost member of Tarzan's tribe. This OC could have unique skills like being an expert tracker or having a special connection with the jungle animals. They could join Tarzan on his adventures and bring a new dynamic to the story.
One interesting idea could be Naruto using new forms of his jutsu to promote peace. For example, he might develop a jutsu that can heal the emotional wounds of people, thus mending the rifts between warring factions.
Another plot could revolve around an OC who is a Spartan trainee that doesn't quite fit the mold. They have a different way of thinking and approaching combat. In Halo 4, they end up being the key to solving a mystery related to the Prometheans. Maybe they find a way to communicate with the Prometheans and convince some of them to stop fighting the humans.
One idea could be an Otsutsuki OC who comes to Earth not for conquest but to study the unique life forms here. They could befriend some of the local ninjas and learn about the concept of friendship, which is alien to the Otsutsuki. This would lead to a series of adventures where they have to protect their new friends from other more hostile Otsutsuki members.
One idea could be an OC who is a long - lost relative of Moana. This OC could have been separated from the family during a great storm years ago. They could have unique skills, like being able to communicate with a different type of sea creature that Moana has never encountered. This would bring new adventures as Moana and the OC try to figure out how this new discovery could help their island.
One idea could be exploring the origin of the OC in the covenant world. Maybe they have a special power that sets them apart from the regular covenant members.