One consequence could be that he becomes extremely powerful. His physical abilities like strength, speed, and endurance are enhanced. He can also use more powerful jutsus with the extra chakra boost from the Kyuubi.
Well, in many fanfictions, Naruto often starts by facing a life - threatening situation. This intense moment somehow triggers a connection with the Kyuubi within him. Maybe it's during a battle against a really powerful enemy that he has no other choice but to tap into that power. It could also be due to some kind of emotional turmoil, like seeing his friends in great danger.
One interesting 'Naruto Kyuubi Chakra' fanfiction could be one where Naruto has better control over the Kyuubi's chakra from the start. It changes the whole dynamic of his early battles and how others perceive him in the village.
In fanfiction, the Kyuubi's Yin chakra in Naruto is often portrayed as a source of great power and mystery. Some fanfictions might show Naruto having to master this part of the chakra to gain new abilities, like enhanced control over illusions or a deeper connection to the spiritual side of his ninja powers.
In fanfiction, the 'Naruto Kyuubi Chakra' often plays a central role in power - ups. It can make Naruto much stronger than in the original story, allowing him to defeat powerful enemies more easily.
One role is to enhance Naruto's combat abilities. It can give him an edge in battles, like allowing for more unpredictable attacks. For example, it could make his shadow clones more versatile.
This wish for unlimited chakra could also have some drawbacks. Naruto might become over - reliant on his chakra and not focus on improving his other skills like taijutsu or ninjutsu strategy. Also, having such an excessive amount of chakra could make him a target for those who want to steal or control it, putting him and his friends in danger.
The fanfic might center around the relationship between Naruto and the fem Kyuubi. Since she is the first chakra user, she could teach Naruto some ancient and powerful chakra techniques. This could lead to Naruto becoming even stronger and more respected in the ninja world. And of course, there could be a bit of a romantic sub - plot as they grow closer.
Naruto would likely develop more control over his chakra with the help of the fem Kyuubi. He might become more mature in his approach to battles and life in general. The fem Kyuubi, on the other hand, could develop more human - like emotions as she spends time with Naruto.
Naruto might be able to develop a new jutsu that combines the Kyuubi's chakra with his wind - style jutsus in a unique way. For instance, he could create a tornado - like jutsu with the raw power of the Kyuubi's chakra at its core. He could also potentially develop a jutsu that uses the Kyuubi's chakra to create illusions that are so powerful they seem real.