Maybe Anko worries about how the fanfiction might distort the original Naruto characters. For example, some fanfictions could make Naruto overly out of character, changing his values or his relationships in a way that doesn't align with the original story.
In a Naruto - Anko romance fanfic, perhaps Anko helps Naruto train in a new jutsu. As they spend time together, they start to develop feelings. Naruto's positive attitude starts to rub off on Anko, and she becomes more open. Their relationship could face challenges from the ninja community as they might not approve of their union due to different reasons, like Anko's past or Naruto's status as a hero.
One possible funny fanfiction could be about Naruto trying to prank Kurenai and Anko at the same time. He sets up a series of comical traps around the training ground. Kurenai, with her sharp perception, starts to notice something is off but Anko just blunders right into the first trap, which sprays her with a bucket of colored water. Naruto is hiding in the bushes trying not to laugh out loud. Then Kurenai pretends not to notice Naruto's presence and lures him out by acting like she's falling for another of his pranks, and when he jumps out, she surprises him with a little genjutsu that makes him see a horde of angry Ankos chasing him.
Perhaps Anko is trapped in a genjutsu and Naruto uses his own experience with breaking free from illusions to save her. He could sense her distress and use his chakra to disrupt the genjutsu, freeing Anko. This would show Naruto's growth and his ability to help those in need, even a more experienced ninja like Anko.
One reason Anko might worry about Naruto fanfiction is the creativity that sometimes goes too far. Fanfictions can explore new ideas, but some might cross the line. For example, they could rewrite the relationships in Naruto in a way that Anko, who is familiar with the original relationships, might not like. Additionally, the spread of inaccurate fanfictions could make it harder for new fans to truly understand the original Naruto story and its intended meanings, which could be a cause for her worry.
There could be. Fanfiction is a vast world where all kinds of ideas are explored. However, I'm not sure specifically which fanfiction sites would have this particular one. You could start by looking at popular Naruto fanfiction platforms like FanFiction.net or Archive of Our Own. Maybe search for 'Anko Naruto sister' on those sites to find relevant stories.
One possible fanfiction could be about Anko seeing Naruto's potential and taking him under her wing for special ninja training. She could teach him some of her unique jutsu, like her snake - related techniques. Naruto, in turn, would bring his own determination and positive attitude, which might start to change Anko's somewhat jaded view of the world.
One challenge could be the reaction of the village. Since Naruto is a well - known figure, the news of him impregnating Anko might cause a stir. There could be rumors and gossip that they would have to deal with.
It could be that Anko is under some sort of mind - control in the fanfiction. And because of that, she attacks Naruto without really meaning to. Maybe she has been influenced by an enemy's genjutsu. So, she uses her powerful attacks on Naruto, and he gets hurt as a result.
One possibility is that Naruto would go into self - exile and train on his own. He might find new powers and allies outside the Hidden Leaf Village. With Anko, she could be conflicted. She might secretly help Naruto, believing that his banishment was unjust. This could lead to a whole new adventure where Naruto has to prove himself worthy without the support of his home village.