The curse mark can change their physical abilities. For Sasuke, it might enhance his speed and strength, but also make him more prone to losing control. Naruto, on the other hand, might develop new chakra - related powers because of his exposure to Sasuke's curse mark. For example, he could gain the ability to sense the curse mark's energy better.
One great fanfiction could be where Sasuke's Curse Mark affects his relationship with Sakura in unexpected ways. Maybe it makes him more withdrawn and Sakura has to find new ways to reach out to him. For example, she might study more about the Curse Mark's origin to better understand what he's going through.
One interesting plot could be how the curse mark affects their relationship. Maybe Sasuke's curse mark starts to make him more aggressive towards Naruto, but Naruto is determined to save him from its dark influence. This could lead to some intense battles and emotional moments between them.
One theme that pops up often is protection. Sakura wants to protect Sasuke from the negative effects of the Curse Mark, while Sasuke, in some stories, tries to protect Sakura from himself when the Curse Mark takes over. Also, there's the theme of growth. Through their experiences with the Curse Mark situation, both characters grow. Sasuke learns to control the mark better, and Sakura becomes stronger in her resolve to be with him.
In some fanfictions, the curse mark can be a source of tension. If Sasuke's curse mark makes him more aggressive or unpredictable, Sakura might be worried about him. For example, he could accidentally lash out at her during a training session. This would put a strain on their relationship as she tries to help him and he tries to keep his distance to protect her from the curse mark's influence.
One great fanfiction could be where the curse mark on Sasuke or Sakura gives them unique powers that they have to learn to control. It might involve them training together to master these new abilities. For example, if Sakura has a curse mark that enhances her strength but also has a dark side, Sasuke could help her control it using his own experiences with the curse mark. This kind of fanfiction often explores their relationship in a deeper way, as they rely on each other more.
One possible plot could be that they get the curse marks from a new, powerful enemy. They then have to figure out how to control the curse marks together without losing themselves to the dark power. Maybe they go on a journey to find a way to remove the marks while also facing challenges from other villages who see them as a threat because of the marks.
In some fanfictions, the curse mark can initially drive a wedge between Naruto and Sasuke. Sasuke might become more withdrawn and brooding due to the power and dark influence of the curse mark. Naruto, on the other hand, would be worried about his friend but might not fully understand what Sasuke is going through. This could lead to some misunderstandings and arguments between them as Naruto tries to reach out while Sasuke pushes him away.
You can try some popular fanfic websites like Fanfiction.net or Archive of Our Own. Just search for 'Naruto Sasuke curse mark' on their search bars, and you might find some relevant fanfics.
The curse mark could have a mind of its own. It starts to communicate with Naruto and Sasuke in their dreams, trying to manipulate them into doing its bidding. Naruto, being the optimistic one, tries to resist and turn the curse mark's power into something positive. Sasuke, however, is more tempted by the power it offers. This could lead to a rift between them as they have different approaches to dealing with the curse mark, and their relationship would be put to the test.