In such a fanfiction, the story could take a very dark turn. Naruto's ideals of friendship and peace might be severely tested. He could be forced to question his own beliefs as Obito and Madara have very different outlooks. Maybe Naruto would try to change their minds, but it would be extremely difficult as they are both very set in their ways of achieving a new world order through more extreme means.
A fanfiction story could start with Naruto being in a desperate situation where he feels that the normal path to peace is not working. So, he decides to team up with Obito and Madara. At first, they seem to be working towards a common goal. But then, Naruto realizes that their means are too extreme. For example, he discovers that the Infinite Tsukuyomi they plan would take away people's free will. He then has to find a way to stop them while still maintaining some sort of alliance. This could lead to a complex web of relationships and power struggles within the group.
One possible fanfic could be where Madara's grandson discovers his family's legacy. He might struggle with the expectations that come with being related to such a powerful and controversial figure in the Naruto world. He could face both admiration and suspicion from others as he tries to make his own mark, perhaps by trying to bring a new era of peace or by exploring new jutsu that were inspired by Madara's techniques.
Yes, there could be fanfics with that plot. Fanfiction writers like to come up with all sorts of crazy ideas to reimagine the Naruto universe. But it's important to note that this goes completely against the official storyline. Naruto is from the Uzumaki clan and has his own origin story which has no connection to Madara in the original series.
On a broader scale, the ninja world would enter a new era. The threat that Madara posed would be eliminated, and Naruto would likely have a major role in shaping the new world order. He might focus on peace - building initiatives and forging stronger bonds between the different ninja villages.
I'm not sure about a specific 'naruto is madara fanfic' off the top of my head. However, if you search on large fanfic archives like FanFiction.net or Archive of Our Own (AO3), and use the tags 'Naruto' and 'Madara' along with something like 'admiration' or 'fan of', you're likely to find some relevant stories. These platforms have a wide range of stories written by fans from all over the world.
The plot could involve Naruto studying Madara's old techniques and strategies. He might be fascinated by Madara's ability to control the Nine - Tails in the past. So, Naruto starts to dig deeper into Madara's history and teachings, trying to incorporate some of his ideas into his own ninja way while still maintaining his core values.
In this kind of fanfic, the author may describe Naruto's resemblance to Madara in terms of their auras. Naruto could have an aura that is as intimidating as Madara's. For example, when he enters a room, people might feel the same kind of pressure as they would when Madara was around. And perhaps Naruto starts to have some facial expressions that are similar to Madara's, like a certain smirk or a serious frown.
Power is a common theme. The gunbai is a symbol of Madara's great power, so fanfics often explore how that power is manifested through it. Another theme is legacy. Since Madara is such an important figure in Naruto, the gunbai can represent his legacy that other characters may interact with.
One great fem Madara x Naruto fanfic is 'A Different Path'. It explores an alternate universe where Madara is female and her relationship with Naruto unfolds in a really interesting way. The author does a great job of building their connection through various adventures and challenges they face together.