One challenge could be the physical exhaustion. Jiraiya's training is likely to be very demanding physically, and Naruto might struggle to keep up with the intense workouts.
One challenge could be the difference in their natures. Madara is an Uchiha with a more cold and calculating style, while Naruto is more impulsive and emotional. Adjusting to Madara's training methods which are likely to be strict and demanding could be tough for Naruto.
During the training, Naruto could face the challenge of balancing his own power with Kurama's. It's not easy to incorporate such a powerful and wild source of chakra into his own fighting style. He also has to face the fact that Kurama's training is not going to be easy - going. There will be setbacks and failures, and Naruto has to keep his motivation high. Moreover, Naruto may have to face the jealousy or suspicion of other ninjas who might not understand his new - found power from Kurama's training.
Jiraiya's serious training helps Naruto a great deal. It makes Naruto more disciplined. He has to follow strict routines and endure tough physical and mental challenges. This helps him become stronger both in terms of his ninja skills and his ability to face difficulties in general.
One of the main challenges could be the lack of immediate feedback. When training alone, Naruto doesn't have a partner to correct his mistakes right away. For example, if he's working on a new jutsu, he might not realize he's performing it slightly wrong until it fails completely. Also, he has to motivate himself without the competition or support of his peers. He might get bored or frustrated easily since there's no one around to cheer him on or push him further.
The training makes Naruto more confident in his abilities. Jiraiya constantly challenges Naruto and as Naruto overcomes these challenges, he realizes his own strength. He starts to believe in himself more, which is evident in the way he faces stronger opponents without hesitation later on. Also, Jiraiya's teachings about the ninja way and the importance of protecting those you love make Naruto more determined and focused on his goals.
He might face challenges like mastering new jutsu. The toads have unique techniques that Naruto has to learn, which could be physically and mentally exhausting.
Jiraiya's training methods in the fanfiction are quite diverse. He may start with basic physical conditioning such as push - ups, sit - ups and long - distance running to build Naruto's stamina. Then, he moves on to chakra - based training. He has Naruto practice chakra control by doing things like walking on water or climbing vertical surfaces using chakra. Jiraiya also teaches Naruto about the different types of chakra natures and how to combine them for more powerful jutsus. Additionally, he arranges mock battles for Naruto against various opponents, which could be either real people or summoned creatures, to improve Naruto's battle strategy and reaction time.
One challenge could be readjusting to the village life. After intense training in a different environment, the daily routines and social norms of Konoha might seem strange. Also, he may face jealousy from some of his peers who haven't advanced as much in their skills during his absence. Another challenge could be dealing with the new threats that Konoha might be facing, and having to prove himself all over again to the village elders that his new skills are useful for the village's protection.
One challenge could be controlling Kurama's powerful chakra. It's so immense that Naruto might struggle not to be overwhelmed by it. If he can't control it well, he could end up harming himself or losing control during the exam.
Jiraiya's training in the fanfiction might focus on Naruto's inner strength as well. He could help Naruto better understand and control the Nine - Tails' power. This new - found control would give Naruto a sense of calm and authority. His character would shift from being just a loud - mouthed underdog to a more respected and powerful ninja. Naruto would also learn about loyalty and sacrifice from Jiraiya, which would shape his values.