Naruto would win. He has a lot of experience fighting powerful opponents and has developed many powerful jutsu over time. He also has the willpower and the ability to adapt in battle. Shukaku is strong, but Naruto's intelligence and his ability to think on his feet would give him the edge.
A plot might involve Shukaku being controlled by an evil force and Naruto has to fight it to save the village. Naruto starts by trying to reason with Shukaku, but when that fails, he has no choice but to engage in a fierce battle. He might call upon the help of his friends like Sasuke or Sakura at some point to create a strategy to defeat Shukaku.
One interesting storyline could be about the relationship between the Shukaku and Naruto evolving in a unique way. For example, the Shukaku might teach Naruto some ancient and powerful jutsu that was once known only to the tailed beasts. This could give Naruto an edge in battles and also deepen their bond.
Kakashi can also be involved in some shukaku naruto fanfic. He could be Naruto's mentor in understanding the Shukaku better. He has a wealth of knowledge about the ninja world and could offer advice to Naruto on how to handle the power of the Shukaku and any potential risks associated with it.
There could be a powerful and jealous ninja from another village. This ninja wants the power of the Shukaku for himself. He sees the relationship between Naruto and the female Shukaku as an obstacle to his goal, so he devises plans to separate them and capture the female Shukaku, making him a major antagonist in the fanfiction.
Their relationship could start with mistrust. Since Shukaku is a tailed beast, Naruto might be cautious. But as they interact more, like when they are forced to fight together against a common foe, they start to respect each other.
A possible plot is that the female Shukaku is captured by an evil organization. Naruto, being the hero he is, sets out on a rescue mission. Along the way, he discovers more about the female Shukaku's past and her connection to the history of the ninja world. This could involve ancient secrets and prophecies related to the tailed beasts.
One idea could be that the female Shukaku has been living in hiding among the Leaf Village. Naruto discovers her secret and they form an unlikely bond as they train together to control her Shukaku powers. This bond then turns into a deep friendship that might lead to more as they face various threats to the village.
A 'naruto vs jigen fanfic' could be really interesting. Naruto is known for his never - give - up attitude. He would likely start the fight with his usual bravado and confidence. Jigen, being a more mysterious and powerful opponent, would probably initially have the upper hand. But Naruto's ability to adapt in battle is remarkable. He could analyze Jigen's fighting style during the fight and come up with new strategies. The fanfic could also introduce new elements like a power - up for Naruto or a hidden ability of Jigen that changes the course of the battle.
I think Hinata could be an ally. She has always been in love with Naruto and would not stand by while he is in danger from Dark Naruto. Additionally, Shikamaru is smart and strategic. He might see the threat of Dark Naruto to the village and decide to assist Naruto, using his intelligence to come up with battle plans.