One possibility could be that Naruto, for some reason, joins the League of Legends world and then betrays the other champions. Maybe he's been influenced by an evil force. For example, he could be tricked into believing that the League is actually a threat to his own world of Naruto, so he turns against them.
Perhaps Naruto is initially excited to be in the League of Legends world. He forms alliances with some of the champions. But then, he discovers a dark secret about the League, like they are using power in a corrupt way. Feeling deceived, he decides to betray the League. He could then start his own rebellion within the League, using his unique abilities like shadow clones and rasengan to fight against the champions who still support the League's old ways.
Well, in a fanfiction like this, it might be that Naruto is brought into the League of Legends universe against his will. He tries to find a way back to his own world but is constantly thwarted by the League's rules and regulations. This could lead him to feel betrayed by the League, and in turn, he betrays them. He might use his ninja skills in unexpected ways that the League champions are not prepared for.
Well, one possibility could be that the Justice League misinterprets Naruto's powers as a threat. Maybe they see his shadow clone jutsu as some form of dangerous cloning that could disrupt the balance in their world. So, they turn on him without really understanding his true intentions.
Naruto's ability to tap into the Nine - Tails' chakra would be a game - changer. In a betrayal scenario, if he's pushed to his limits, he could unleash the power of the Nine - Tails. This would make him extremely powerful, perhaps even on a level that the League of Legends champions have never faced before. He could use this power to fight against the League, causing massive destruction and upheaval in the League's world.
The fanfiction might revolve around a team in League of Legends. One of the members experiences a loss of mind because of a personal tragedy off - the - field. This could be something like the loss of a loved one or betrayal by someone they trusted. Their mental state then affects their performance in the game and the overall dynamics of the team.
One possible plot could be that Jiraiya is forced to betray Naruto due to some external threat. Maybe an enemy has captured Jiraiya's loved ones and threatened to kill them if he doesn't turn on Naruto. Jiraiya, in a difficult position, might have to pretend to be against Naruto to protect his loved ones while secretly trying to find a way to free both Naruto and his family from the enemy's clutches.
Well, one possibility could be that Mavis has some sort of hidden agenda. Maybe she's being controlled by a greater evil force that makes her turn on Naruto. It could also be a misunderstanding. For example, false information is spread about Naruto, and Mavis believes it without proper investigation. Another idea is that Mavis has a different view of the ninja world compared to Naruto, and their conflicting ideologies lead to her betraying him.
Well, it could be that Kurenai is somehow deceived into believing Naruto has done something really bad. Maybe she's tricked by an enemy who fakes evidence against Naruto. So, in her misunderstanding, she turns against him.
In this fanfiction scenario, perhaps Mirajane has her own dark secrets or hidden motives that lead to her betraying Naruto. She might be seeking power and sees Naruto as an obstacle. Or, it could be related to loyalty to her own guild or group. If there are conflicting interests between Naruto's world and her world, she might choose to side against Naruto to protect her own people.
Well, it could be that they betray their village. Maybe they are tricked into believing false information about Konoha being corrupt. So they side with an enemy force, thinking they are doing the right thing.
Well, one possibility is that Naruto is framed for a serious crime he didn't commit. Maybe someone fakes evidence that he's been working with the enemies of the village. His friends, believing the false evidence, turn their backs on him. He then has to fight not only against the village's distrust but also to clear his name and find out who really set him up.
Perhaps Hiruzen is being influenced by some dark force or a hidden group within the village. They convince him that Naruto, with the Nine - Tails inside him, is too dangerous to be left unchecked. So, Hiruzen, in a moment of weakness, decides to betray Naruto. He could secretly arrange for Naruto to be sent on dangerous missions alone with the intention of getting him killed. Naruto, being oblivious to this at first, later realizes what's going on and has to fight not only against external enemies but also against the betrayal of his own village leader.