In this fanfiction, the plot might be centered around Karin replacing Sakura in a mission or a task within the fictional world. For example, if they are in a ninja - like setting, Karin could use her unique abilities instead of Sakura's to achieve a certain goal. This could lead to different interactions with other characters who were used to working with Sakura.
One popular type might be those set in a magical world where karin, with her own unique abilities, steps into a role that sakura once had. For example, in a story where a magical tree that was once associated with sakura now has karin as its protector. Karin's different personality traits, like her being more headstrong perhaps, can lead to different interactions with the other characters in the fanfiction.
Well, Karin is for sure a main character as she is taking over Sakura's position. Sakura, although being replaced, still has an important role as the benchmark for Karin's replacement. Then, other characters in their shared universe who interact with either of them could be main characters too. For instance, Naruto could be involved, seeing as he is friends with Sakura and may have some sort of reaction to Karin replacing her. Also, characters from their respective teams or groups might be main characters as they would be affected by this replacement.
Often, the plot starts with the sudden or gradual replacement of sakura by karin. This could be due to a spell, a twist of fate, or a decision made by some higher power in the fictional world. Then, karin has to deal with the consequences and expectations that were previously associated with sakura.
Often, Sakura is depicted as kind - hearted. She is the one who is more likely to see the good in people. Karin, on the other hand, might be more headstrong. For example, when they face a difficult situation, Sakura will try to find a peaceful solution first, while Karin is ready to jump into action right away.
In the realm of fanfiction, almost any scenario is possible. Regarding Sasuke divorcing Sakura for Karin, it may exist. Fanfiction authors draw inspiration from the source material and then take it in new directions. The idea might stem from Karin's past feelings for Sasuke and some fans' desire to see how such a relationship shift would impact the characters. It could also be a way to explore the characters' personalities more deeply, for example, how Sakura would cope with such a betrayal and how Karin would handle being with Sasuke in that context.
There probably is. Fanfiction writers like to take existing characters and create different storylines. But it's important to note that this isn't part of the official Naruto story. In the original, Sasuke and Sakura are a couple, and Karin has her own relationship with Sasuke which is more of comradeship in the official plot. Fanfiction just gives people the freedom to deviate from the original.
There could be. Fanfiction writers sometimes come up with very creative and sometimes controversial ideas. However, this particular plot would be quite a deviation from the original story's themes of loyalty and friendship. In the original, Sasuke has his own complex relationships that don't involve such unfaithful behavior in this way.
The theme of cooperation also pops up a lot. Since they have different abilities, fanfictions often explore how they can work together. For instance, Sakura's knowledge of herbs and healing combined with Karin's knowledge of the chakra flow can lead to some interesting storylines where they solve problems or face enemies as a team.