In a fanfic about Freedon Nadd in a reincarnation OC setting, the power dynamics would be crucial. Freedon Nadd was a powerful Sith Lord. If the OC is reincarnated in the same universe, they might have to deal with the lingering influence of Nadd. The OC could either be in a position to oppose him, perhaps with some unique power or knowledge from their past life, or they could be unknowingly influenced by him. This kind of interaction can lead to a great exploration of good vs evil and the struggle for power.
One unique feature is the combination of different universes. For example, in a Naruto - Bleach crossover, you get to see Naruto's chakra system interact with Bleach's reiatsu. Another is the new character developments. Reincarnation often gives Naruto or other characters new backstories and abilities. Also, it can bring fresh plotlines like in a Naruto - One Piece crossover where Naruto might have to deal with the concept of Devil Fruits in a new way.
One way to incorporate Freedon Nadd is to have the OC discover an ancient artifact related to him. This could trigger memories or visions of Nadd's time, and set the OC on a journey to learn more about this powerful figure. For instance, the artifact could be a Sith amulet that once belonged to Nadd, and when the OC touches it, they start seeing glimpses of his past and the events he was involved in.
The theme of destiny also frequently appears. Many fanfictions suggest that Christina's reincarnation is not a random event but part of a greater destiny, perhaps related to saving the world from some great evil in the Vampire Diaries universe. There's also the theme of power. As she adjusts to her new life, Christina may gain new powers or have to deal with the power struggles among the different supernatural species.
Well, 'Naruto's Reincarnation in the Attack on Titan World' is a fascinating 'naruto crossover recarnation fanfiction'. In this story, Naruto has to face the Titans with his ninja abilities, and the contrast between the two worlds makes for an exciting read. Then there's 'Naruto Reincarnated in the My Hero Academia World'. It's interesting to see how Naruto's powers would be perceived in a world full of quirks. Another good one is 'Naruto's Reincarnation in the Code Geass World' where Naruto's reincarnation disrupts the political and power - play of the Code Geass universe.
The difference might lie in the rules. Regular reincarnation stories often follow certain spiritual or religious rules about karma and rebirth. But a 'not your typical' one could break those rules. For example, in a regular story, a good soul might be reborn into a better situation, but in this type of story, it could be the opposite.
Well, it could be a story where the process of reincarnation is not linear. In typical reincarnation stories, there's a sort of cause - and - effect chain. But in this 'not your typical' one, the reincarnation might be random or influenced by some external, unheard - of forces. Maybe the soul jumps from one time period to another without any connection to its past lives in the way we usually think. It could also have elements of magic or otherworldly beings that are not usually associated with the normal reincarnation concept.
One popular Vampire Diaries Christina Recarnation fanfiction is 'A New Beginning for Christina'. It explores the idea of Christina's reincarnation in the Vampire Diaries world in a really interesting way. The author does a great job of fitting her character into the existing storylines and relationships.