Well, a cool concept is the transformation of the OC's personality over time in the reincarnation fanfiction. Since they have memories from another life, they might start off as a bit of an outcast, being different from the others in the RWBY world. But as they interact more and more, they gradually change. Another aspect is the power evolution. Their powers from the past life could merge or transform in this new world. For instance, if they had the power of elemental control in their past life, it could manifest in a new and unique way in RWBY, like being able to control Dust in a way no one else can.
One interesting concept could be the reincarnation aspect. It allows for the OC (Original Character) to have a new start in the RWBY universe, perhaps with knowledge from their past life that gives them an edge. Another concept might be the harem part, which could lead to various relationship dynamics and character interactions within the story.
Well, when creating a RWBY OC for reincarnation fanfic, you need to think about their motivation deeply. What drives them in this new life? Is it to correct the mistakes of their past life? Or perhaps to find someone they knew before. Their backstory should be detailed and not just a simple 'they were a warrior'. For example, they could have been a part of a secret society in their past life that had knowledge about a great power. In the RWBY world, this knowledge could be the key to defeating Salem. Their appearance can also reflect their past life. If they were from a cold climate in their past life, they might have a preference for warmer clothes in RWBY. And don't forget their character arc. They should grow and change as the story progresses, learning from their past life and the new experiences in RWBY.
Another plot could involve the OC reincarnating into an existing character's body. This would lead to a lot of internal conflict as they try to adjust to the new identity while still having memories of their past self. They could also use their new position to change the course of events in the RWBY universe.
The character could start off being confused about their new situation. As they interact with the RWBY characters, they gradually learn about the values of this new world. For example, learning about teamwork from Team RWBY and applying it to their own growth.
First, give each character in the harem a distinct personality. For example, one could be a strong and silent type, while another is very outgoing and bubbly. Then, show how they interact with the OC. Their reactions to the OC's reincarnation and unique traits can shape their development. For instance, if the OC has a special power, some characters might be in awe, while others could be jealous.
One idea could be that the OC reincarnates into the RWBY world with some unique powers from their past life. These powers attract the attention of different characters, gradually forming a harem. For example, their power could be related to some ancient magic that is both feared and desired in the RWBY world.
An OC in a RWBY Reincarnation fanfic could be reincarnated with the ability to see the future. This would be a great advantage but also a burden as they see the potential doom of their friends and the world. They would have to decide whether to tell others or try to change the future on their own. Another concept is an OC who was a famous artist in their past life and is now reincarnated in RWBY. They could use their artistic skills to create unique weapons or help in other creative ways in the fight against Grimm. And a third one could be an OC reincarnated as a spirit - like being that can possess other objects or people, which would lead to some very strange and interesting plot twists.
Well, of course, Ruby would be a common character. She's the main protagonist in RWBY, so it's natural for her to be part of the story. Yang Xiao Long could also be involved. Her protective and fiery personality would add a lot to the harem dynamic. Pyrrha Nikos might also be included. Even though she had a tragic end in the original series, in fanfiction, she could have a new role in the OC's harem, adding an element of redemption or second chances.
In fanfiction, the idea of oc being the reincarnation of Roger can be a very interesting and complex concept. It can bring in elements of fate, destiny, and the cyclical nature of life. The oc might inherit some of Roger's qualities, either consciously or subconsciously. For example, they could have a similar sense of adventure or a hidden knowledge about things that Roger knew. This concept also gives the author a chance to explore how the world of One Piece (assuming it's a One Piece fanfiction) would react to the presence of someone who could potentially be a reincarnation of the great Pirate King. It can lead to many different story arcs, such as the oc being hunted by those who want to use Roger's power or being revered by those who believe in Roger's ideals.