There's also a sense of confusion. Naruto is lost without Jiraiya's guidance. He's not sure how to move forward in his journey to become Hokage and how to deal with the new threats to the village without his master's wisdom.
Naruto can be angry too. Angry at himself for not being strong enough to protect Jiraiya, or angry at the circumstances that led to his death. This anger sometimes manifests in his training or in his interactions with others.
He is often shown as being extremely sad. Jiraiya was like a father figure to Naruto, and his death leaves a huge void in Naruto's life.
He might become more determined. Losing Jiraiya was a huge blow, but it could fuel his desire to become stronger and protect the village even more.
One possible scenario could be that Naruto leaves to train in isolation. He might feel that he needs to become stronger on his own without the guidance of Jiraiya, and so he sets off to find new ways to improve his skills.
In fanfiction, Jiraiya's death can also be used to explore themes of sacrifice. He sacrificed himself for the greater good, and this can be further elaborated in different stories. For example, some fanfictions might show how his death inspired other characters to be more selfless.
Kakashi could step up more as a mentor. He already has a connection with Naruto and could help him develop his skills further.
Naruto might also isolate himself in certain fanfic scenarios. He feels that no one can truly understand the depth of his grief. He spends time alone, reflecting on all the things Jiraiya taught him and the memories they shared, like their time training on that toad -infested island.
Naruto is devastated. He feels a huge void in his heart. Jiraiya was the one who believed in him from the start, and his death makes Naruto question a lot of things. He might even start to doubt his own strength for a while.
His character may become more withdrawn at first. Losing Jiraiya, who was like a father figure to him, could make Naruto less open and more focused on his internal pain.
One scenario could be that Jiraiya is poisoned before his fight with Pain. In the fanfiction, an enemy within the village who is secretly working for Pain's forces might have poisoned his food or drink. So, when he goes to face Pain, he is already weakened, and this ultimately leads to his death. Another possibility is that Jiraiya's death is a result of a time - traveling plot. If there is time - travel involved in the fanfiction, his actions in the past might accidentally create a situation where he has to die to preserve the timeline.
Sometimes Naruto copes by throwing himself into his training. He uses the pain of losing Jiraiya as fuel to become stronger.
One common theme is mentorship. Jiraiya was Naruto's mentor, so many fanfictions explore how his teachings shaped Naruto's growth as a ninja. For example, Naruto might use a specific jutsu Jiraiya taught him in a unique way to overcome an enemy.