It could be Orochimaru. Since Orochimaru has a long - standing feud with Jiraiya and is always up to no good. If Naruto ditches Jiraiya, Orochimaru might see this as an opportunity to manipulate Naruto. He could try to convince Naruto that Jiraiya was holding him back and that he can offer Naruto more power, all while having his own evil plans for Naruto.
It can create a sense of growth for Naruto. Without Jiraiya by his side, he has to rely more on his own instincts and the skills he has already acquired. This can lead to new character development as he faces challenges alone.
Tsunade and Jiraiya had a complex relationship. They grew up together as comrades in the Hidden Leaf Village. Jiraiya had deep feelings for Tsunade. However, Tsunade was often hesitant. Jiraiya was a bit of a free - spirited and adventurous type, while Tsunade was more reserved and burdened with her past traumas. Their love was more of an unspoken and underlying current in their relationship, often overshadowed by their duties and the chaos in the ninja world.
In this fanfiction concept, it could lead to a really interesting dynamic. Jiraiya is a powerful and eccentric ninja. He could teach Naruto some really unique jutsu, like more advanced forms of Rasengan. And their relationship would be filled with Jiraiya's boisterous personality clashing and also complementing Naruto's determination.
It started from their shared experiences. As they trained and fought together, Jiraiya began to notice Tsunade's many qualities. Tsunade, who was initially just seeing Jiraiya as a comrade, gradually noticed his deep affection for her. His little gestures, like bringing her small gifts or always being the first to volunteer to be her partner in missions, made her heart soften towards him over time.
Jiraiya's story concludes in Shippuden. It's a heartbreaking part of the storyline that leaves a lasting impression. His death sets the stage for many important events and motivations for the other characters.
One possible reason could be that Naruto feels he has learned all he can from Jiraiya at that point. Maybe he wants to explore his own path independently and test his skills without Jiraiya's constant guidance.
Jiraiya's reaction might be complex. He might be in awe of Naruto's new power but also sad about his departure. He could see it as a natural progression in Naruto's journey, yet still feel a pang of loneliness. He might start to reflect on his own life and training methods, wondering if he could have done something differently to keep Naruto with him. At the same time, he would be eager to see what Naruto will achieve in the world with his newfound abilities.
They often make him seem irresponsible. For example, in normal Naruto story, Jiraiya is seen as a mentor to Naruto. But in bashing fanfiction, he may be shown as being more interested in his own adventures and leaving Naruto alone at crucial times.
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.