One idea could be to introduce a new character who has a special skill, like being an expert archer from a far - off land. This character could initially be distrusted by the group but then prove their worth in a big battle. Another idea is to have a plot centered around a lost treasure that the group has to find while also dealing with a rival gang who wants it for themselves. Maybe the OC could have a personal connection to the treasure's origin.
A great plot could be that the OC in the 'the magnificent seven oc fanfiction' is a healer. However, there is a shortage of the special herbs needed for the healing in the area they are in. So, the group has to embark on a journey to find these herbs. Along the way, they face various challenges, like crossing a dangerous river and dealing with bandits. This not only tests their physical strength but also their loyalty to each other.
A great plot for Magnificent Seven fanfiction might be a love story within the group. Perhaps one of the members falls in love with a local girl they are protecting. But there are complications, like her father doesn't approve because he thinks the man is too dangerous. And at the same time, they still have to face off against the bandits that are threatening the town. So it's a story of love and duty all mixed together.
A great idea for the fanfiction could be to develop a romantic sub - plot among the characters. Since they are in a group, there could be some unspoken feelings or a slow - burn romance that starts to develop between two of them. This could add a new layer of depth to the story and also show a different side of the characters, as they navigate their feelings while still dealing with the main adventures and challenges in their world.
One idea could be an OC who is a hybrid of two of the deadly sins, like pride and envy. This OC could struggle with the internal conflict of these two powerful emotions. For example, being envious of the power of other characters while also being too proud to admit it or ask for help. Another plot could be an OC who is on a quest to redeem the Seven Deadly Sins themselves, believing that they can be reformed. This would involve the OC facing many challenges and having to understand the true nature of each sin.
Another interesting concept is an OC who is from a completely different dimension but gets drawn into the Trinity Seven world. This OC could have a different set of values and magic rules from their own dimension, which would create a lot of interesting interactions and conflicts with the existing characters.
A mysterious stranger from a foreign land with unique magical powers. Maybe he can control the elements to some extent. He could be initially reluctant to get involved in the group's affairs but is eventually drawn in by their sense of justice and the need to fight against a common evil.
One interesting fanfiction could be about an alternate ending where one of the characters survives a seemingly fatal situation. It gives a different perspective on the story's conclusion.
A plot could revolve around a time - travel fanfiction. Maybe a character goes back in time and has to prevent an event that would have a catastrophic effect on the future of the Trinity Seven world. This could involve interacting with younger versions of the characters and changing their fates.
One plot idea could be that the OC is a traveler who stumbles upon Okamisan and her companions in a magical forest. The OC has a special power that is needed to save the forest from a dark curse, and through their adventures together, a deep bond forms between the OC and Okamisan.
One idea could be creating an OC (Original Character) who is a descendant of one of the main characters in 'Seven Deadly Sins' and has a unique power related to one of the sins. For example, an OC who is a descendant of Meliodas and has a power that is a variation of his 'Full Counter' ability but is related to the sin of wrath. Another idea is to make an OC that is from a different kingdom entirely and has to deal with the chaos caused by the Seven Deadly Sins. They could start off as an antagonist but later realize the true nature of the sins and join them.
Perhaps a crossover where the Trinity Seven characters enter a post - apocalyptic world. Their magic would be both a great asset and a source of danger as other survivors might see them as threats or saviors. They'd have to figure out how to survive and maybe even find a way to restore the world using their powers.