Fanfiction about 'Dark Naruto, Kyuubi, Memory Seals' can take many forms. One possibility is that the memory seals are tampered with by an outside force. This could be an enemy who wants to unleash the power of the Kyuubi and corrupt Naruto. The 'Dark Naruto' that emerges might have different abilities compared to the regular Naruto. He could be more aggressive and less hesitant to use the Kyuubi's power without the moral restraints that the original Naruto has due to the disrupted memory seals.
Well, in the realm of fanfiction, 'Dark Naruto' related to the Kyuubi and memory seals can be really interesting. The Kyuubi is a powerful and complex entity. Memory seals are a way to keep its power in check within Naruto. When it comes to 'Dark Naruto', it could be that the memory seals are a part of what defines his 'dark' side. For example, if the memory seals were placed in a way that suppresses Naruto's positive memories of his friends and family, the Kyuubi's influence could be magnified, leading to a 'Dark Naruto' who is more isolated and power - hungry, seeing the world in a more negative light because of the altered state of the memory seals.