Maybe there's a plot where Naruto is influenced by an external force that makes him act like the Joker. He then starts to target the powerful figures in the ninja world, not to defeat them in a traditional sense, but to expose their weaknesses and make them look foolish, just like the Joker does with Batman. And as he does this, his relationships with everyone around him start to crumble.
A plotline could involve Naruto using his new - found Joker - like behavior to infiltrate enemy organizations. He'd act erratically and unpredictably, causing internal strife within those groups. However, as he goes deeper into this role, he risks losing his true self and becoming a real threat to the peace he once fought to protect. This would create a complex situation where his friends have to decide whether to save him or stop him.
One possible plotline could be Naruto getting some of Kaneki's ghoul - like powers. So he has to deal with the hunger for human flesh in a way that's similar to Kaneki's struggle, but in the Naruto universe. Maybe he tries to resist it while still protecting his village.
Another plotline could involve Naruto being influenced by an external force that makes him adopt the Joker - like mentality. He could start to form his own 'gang' of sorts, made up of outcasts and misfits in the village. Together, they could start to undermine the authority of the village elders, just like the Joker undermines the power structure in Gotham. This could lead to a series of conflicts between Naruto's group and the traditional shinobi forces in the village.
One possible plotline could be Naruto starting to manipulate the political situation in the ninja world. Just as Aizen had his own designs on the Soul Society, Naruto could use his influence to create power imbalances among the ninja villages for his own gain. Another could be Naruto using his new - found Aizen - like charm to deceive his friends into following a path that they don't fully understand. He might make them believe that he is still the same Naruto, but his actions would be leading them astray.
One plotline could be Naruto getting involved in underground ninja activities like Zabuza used to. He might take on assassination - like missions in the shadows, which would put him at odds with the Leaf Village's more ethical code. Another could be his old friends trying to bring back the real Naruto. They would set out on a journey to find out what made him change and how to reverse it. Also, he could form an unlikely alliance with some of Zabuza's former associates who recognize his new behavior and see an opportunity to use him for their own gains.
Well, he might start to have a more unpredictable nature. Maybe he'd play pranks on his friends in a more extreme and unhinged way, like the Joker's chaotic actions.
One plotline could be Naruto going on a journey to write a book about the ninja world, just like Jiraiya did. Another could be Naruto using Jiraiya's flirting techniques on Sakura, which would create a lot of comical and awkward situations. Maybe Naruto starts his own toad - summoning school, inspired by Jiraiya's connection with the toads.
One possible plot twist could be that Naruto's friends think he's been possessed or something. They would try to find a way to bring the old Naruto back. Another could be that Naruto's new attitude actually makes him a more powerful ninja, which causes some jealousy among his peers.
One possible plot could be that Naruto, for some reason, decides to adopt Sasori's more calculating and detached approach to combat. He might start using puppets or puppet - like techniques in battles, much like Sasori did. Maybe he's on a mission where he has to infiltrate an enemy base and he thinks acting like Sasori would be the best way to succeed.
One possible plot development could be Naruto getting into more intense battles with stronger opponents. Since Kenpachi is always seeking strong battles, Naruto may start to do the same. This could lead to him exploring new areas to find worthy foes.
One reason could be for strategic purposes. Itachi was a highly strategic ninja. So, in fanfiction, Naruto might act like him to outwit a particularly difficult enemy. For instance, when facing an enemy who is a master of deception, Naruto could adopt Itachi's calm and calculating demeanor to see through the enemy's tricks.