The OC could be integrated into the story by having a shared past with either Eragon or Murtagh. Maybe they grew up in the same village as Eragon but were separated when the Ra'zac attacked. Years later, they reunite and the OC can offer some unique perspective or ability to the situation. Or, if the OC has a connection to the dragons in a different way than Eragon and Murtagh. For instance, the OC might have a special bond with a dragon that was thought to be lost. This would bring them into the story as they try to protect their dragon friend and get involved in the events related to Eragon and Murtagh. Also, the OC could be a trader who has information about the movements of the enemy forces. They could trade this information to Eragon and Murtagh in exchange for protection or some other favor, thus becoming part of the story.
Saphira is often a popular character. Since she is Eragon's dragon, she can add a lot of depth to the story. Her unique abilities and her relationship with Eragon can influence the interactions between Eragon and Murtagh in the fanfiction.
One idea could be an OC who is a healer in Alagaësia and gets caught in the middle of the conflict between Eragon and Murtagh. They could try to use their skills to heal the wounds of both sides, physically and emotionally. Another could be an OC with a special power related to magic that neither Eragon nor Murtagh have seen before, and this power could either be a threat or an advantage in the ongoing battles. A third idea is an OC who is from a different part of Alagaësia and has a different cultural perspective on the whole dragon - rider situation. This OC could try to broker peace between Eragon and Murtagh, bringing in new ways of thinking about their roles and destinies.
One interesting eragon murtagh fanfiction could be about their adventures together in a new land. Maybe they discover a hidden magic that was unknown in the original books.
There could be a fanfiction where Murtagh and Eragon form an unexpected alliance later in life. They put aside their past differences and join forces to fight a new, greater evil that threatens Alagaësia. This would involve a lot of character development for both of them as they learn to trust each other again.
There are some out there. Some of them explore the complex relationship between Eragon and Murtagh in a romantic way. They might delve into how their shared experiences could lead to a deeper emotional connection. However, the quality can vary, so it's best to read the reviews or summaries first.
You can try websites like FanFiction.net. It has a large collection of fanfictions, and you can easily search for eragon murtagh fanfiction there. Just type in the relevant keywords in the search bar.
In some fanfictions, there might be a plot where they discover a hidden magic that is related to their pasts. Maybe it has something to do with their families and they need to work together to unlock the secrets. For example, they could find an ancient scroll that only they can decipher due to their bloodlines, and this could lead to all sorts of adventures and revelations.
You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own (AO3). These platforms have a large collection of fan - created works, and you can search specifically for murtagh eragon fanfiction using the search bar.
A common theme is adventure. Since Murtagh is often involved in action - filled storylines, the OC usually joins him in his adventures. Another theme is romance. Writers might pair the OC with Murtagh in a romantic relationship, exploring their chemistry and how they grow together.