The fear might be manifested in the Kyuubi's attempts to negotiate with Naruto rather than fight. In fanfiction, the Kyuubi could offer Naruto things or make promises in order to avoid a situation where Naruto uses his power against it. This shows that the Kyuubi is aware of Naruto's strength and is scared of the consequences of going against him.
In this type of fanfiction, the fem Kyuubi's possessiveness might be manifested in her protecting Naruto at all costs. She could be overly vigilant and not allow any harm to come near him. This could lead to her interfering in battles or situations where Naruto might be in danger, even if he doesn't necessarily need her help all the time. She may also try to monopolize his time, not wanting him to go on missions with other people or make new friends. Her possessiveness could also be expressed in a more emotional way, like getting sulky or angry when Naruto doesn't pay enough attention to her.
She might be overly protective of Naruto in fanfiction. For example, she could prevent other characters from getting too close to him or interfere when she thinks Naruto is in a potentially harmful situation.
One way it could manifest is in his training methods. He might be more strict and dedicated with Naruto compared to other students. He could also try to monopolize Naruto's time for training, not wanting other ninjas to interfere with Naruto's growth under his guidance.
Well, in certain fanfic concepts, Naruto could control Kyuubi chakra with the help of unique jutsu or seals. For example, he might discover a new sealing technique that allows him to better manage the flow of the Kyuubi's power. This new seal could work in harmony with his own chakra system, enabling him to draw on the Kyuubi's strength without being overwhelmed. Also, some fanfictions might suggest that his strong emotional bonds, like his friendship with his comrades, give him the extra mental fortitude to control such a powerful chakra source.
Naruto might initially be shocked and angry. He has always considered the Kyuubi as an enemy within him, and now being kidnapped by it is the worst - case scenario for him. He could try to fight back immediately, using whatever little chakra he can muster without relying on the Kyuubi's power.
At first, Naruto might see the Kyuubi as just a source of power. But as he starts to protect it, he realizes it's more of a partner. Their relationship evolves from a simple user - power source dynamic to a deep - seated friendship. He begins to understand the Kyuubi's emotions and past, which further cements their bond.
In this fanfiction, their relationship becomes more of a partnership. Instead of Naruto just using the Kyuubi's power, they work together as brothers. Naruto might start to understand the Kyuubi's feelings and motives better.
In such fanfiction, their relationship often develops through mutual respect. Naruto no longer sees Kyuubi just as a source of power but as a friend. Kyuubi, in turn, starts to value Naruto's determination and kindness. They might have heart - to - heart conversations in Naruto's mindscape, sharing their past traumas and hopes for the future.
In Naruto fanfiction, Kyuubi can help Naruto by providing him with extra power. For example, it can enhance Naruto's physical abilities like strength and speed during battles. This allows Naruto to face stronger opponents more easily.
Naruto might become more in tune with the Kyuubi's power. He could access more of its chakra easily and use it more effectively in battle. For Hinata, she may gain a new sense of boldness. The training could make her less shy and more assertive in combat situations.