Yano Koji and Tan Kai were two different people. Yano Koji was Japanese. He was born on January 21, 1970 in Osaka Prefecture, Japan. He was a Japanese film actor and host who developed in China. Tan Kai was a male actor in Chinese film and television. He was born on January 13th, 1972 in the Qingdao City, Shandong Province. He graduated from the Central Academy of Drama with a major in stage design. Although the two of them looked very similar, they were not the same person.
Well, 'isekai' usually refers to a genre where the protagonist is transported to another world. 'Koji in' is a bit of a mystery here. It could be a special place, object or even a concept within the world of the light novel. Maybe the story follows the adventures of the one who opened this 'koji in' in the isekai world.
Jiraiya might comfort Naruto by sharing his own experiences. He could tell Naruto about the times he faced difficulties and how he overcame them. For example, he might talk about his training with the toads and how he grew stronger through perseverance.
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.
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.
Jiraiya is frequently shown as a very dedicated mentor. He is willing to sacrifice his own time and resources to train and guide his students. In some fanfictions, he goes to great lengths to protect his students from harm, even putting his own life on the line. This selfless aspect of his character is often emphasized.
First, you could search for it on official light novel publisher websites. If that doesn't work, try some fan - based translation communities. However, be aware that the translations in those communities might not be of the highest quality or legal in all regions. Also, keep an eye on social media groups dedicated to light novels, as someone there might be able to point you in the right direction.
Perhaps in this fanfiction, Jiraiya discovers that Naruto is going to be the cause of a major catastrophe in the future. He might have seen a prophecy or some sort of sign that convinces him Naruto has to die to prevent this. It could also be that Jiraiya has been misled by false information about Naruto, which makes him think that Naruto has become an evil force that needs to be eliminated.