Well, it depends on the specific fanfiction. Some fanfictions might make Naruto Tobirama's grandson to explore new storylines. For example, they could use this relationship to explain Naruto's strong chakra or his natural leadership skills. It could also be used to introduce new conflicts or alliances within the Naruto world that are not present in the original series.
Yes, there could be such fanfics out there. Fanfic writers often come up with creative family relationships that deviate from the original Naruto storyline. They might explore how Naruto's character would be different if he had such a relation to Tobirama. Maybe in these fanfics, Naruto could inherit some of Tobirama's unique jutsu or characteristics, which would add a whole new dimension to his character development and the overall story.
Perhaps in this fanfiction, there's a secret prophecy about Naruto being the grandson of Madara and Tobirama. This leads to a lot of political intrigue within the village. Some people want to use Naruto for their own gain, while others are afraid of what his true heritage might mean for the future of the Hidden Leaf.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Naruto grandson of Tobirama' and you'll find a variety of stories with different plotlines, some might focus on his relationship with the Hidden Leaf Village, others on his unique jutsu inherited from Tobirama.
One consequence could be a change in how Naruto is perceived in the village. Since Tobirama was an important figure, Naruto might be held to an even higher standard. Also, it could affect Naruto's relationships with other characters. For example, some might be more deferential to him.
No, in the official Naruto and Mortal Kombat canons, Naruto has no relation to Sindel at all. But fanfiction is a place for wild ideas. Maybe the author of that particular fanfiction had a really strange and interesting dream that led to this idea of Naruto being Sindel's grandson. It might be part of a much larger and complex story within the fanfiction that combines the ninja world of Naruto and the dark, fantastical world of Mortal Kombat.
There could be a backstory where Madara and Tobirama had a secret agreement that led to Naruto's existence. Maybe they foresaw a future threat and planned for Naruto to be born with their combined power to save the ninja world. Naruto would then have to uncover this mystery and fulfill his destiny.
One plotline could be Naruto having to deal with the expectations and legacy of Tobirama. Since Tobirama was a great shinobi and one of the founders, Naruto might feel pressured to live up to that. Another could be the discovery of this lineage leading to new enemies targeting him.
In some fanfictions, it might be possible for Naruto to be portrayed as Madara Uchiha's grandson. Fanfiction often takes creative liberties and twists established relationships. However, in the original Naruto storyline, there is no such relation.
In most Naruto fanfiction, anything can be possible. However, in the original Naruto series, Naruto has no relation to Uchiha Madara in this way. But in some creative fanfictions, the author might create a complex backstory to make Naruto be Madara's grandson. Maybe they rewrite the history, or use some magic - like elements to connect them.
One possible plot could be that Naruto discovers his relation to Tobirama later in his life. This new knowledge makes him strive to learn more about his ancestor. He might search for Tobirama's hidden techniques and knowledge. Along the way, he could face opposition from those who don't want him to gain such power, thinking it would disrupt the balance in the village.