Perhaps the lemons are a form of currency in the demon realm. Naruto, in his interactions with the demon king, has to trade lemons for information or help. This could lead to comical situations as Naruto tries to gather enough lemons, and also serious moments when the demon king demands more lemons than Naruto can easily obtain.
Well, one way is through a training arc. Imagine Naruto's training takes him to a secluded place where an old master lives. The master has a unique training method that involves wearing a Yukata while performing certain ninja techniques. Naruto would have to adapt to the new clothing style while still maintaining his ninja abilities. Also, Naruto could be involved in a rescue mission where the kidnapped person is held in a place where Yukata are an important part of the environment. He might have to disguise himself in a Yukata to blend in and save the day.
It could also be a character - based integration. A new character inspired by Dark Naruto could be introduced into the RWBY fanfiction. This character might have similar traits such as a thirst for power and a bit of an anti - hero complex. They could interact with the existing RWBY characters, causing conflict and also growth among them.
Well, in a Young Justice fanfiction, the concept of Naruto being immortal could be integrated in various ways. One way could be through some sort of magical or scientific experiment gone wrong that gives him immortality. Maybe it's a meta - human experiment in the Young Justice universe that accidentally gives Naruto the same powers as Vandal Savage, including immortality. Another possibility is that it could be a result of a powerful jutsu he uses that has unforeseen consequences and makes him immortal.
One way to integrate it is to have a mad scientist - type character introduce the nanites into Naruto's body. Maybe this character is an outcast from a hidden village who has been secretly researching nanotechnology. He sees Naruto as a perfect test subject and implants the nanites without Naruto's full knowledge at first.
In this fanfiction, perhaps Sasuke could be a sort of anti - hero. He might initially be seen as a threat by the Demon Slayer corps because of his dark powers. But then, as the story progresses, he could use his Sharingan to detect demons more easily and work with the protagonists to defeat stronger demons.
One possible fanfiction idea could be that Hinata discovers Naruto has a half - demon side that he's been hiding. This could lead to a lot of interesting character development. Hinata, being the understanding person she is, might help Naruto come to terms with this part of himself. It could also introduce new powers and abilities for Naruto, and perhaps a new level of relationship between the two.
In some fanfictions, the demon king might be a misunderstood entity. The lemon aspect could be related to a special power source. For example, Naruto discovers that the lemons can be used to either control or befriend the demon king. This could lead to a series of adventures where Naruto tries to use this knowledge to his advantage while also facing opposition from those who fear the demon king.
In this fanfiction idea, Naruto being the Silent King of the Dead could bring a whole new dimension to the Naruto universe. He might possess powers over the dead, which could be used for various purposes like protecting the Hidden Villages in a different way. Maybe he could communicate with the souls of the past Hokages for advice and wisdom.
If Naruto were in the King of Pirates' world in a fanfiction, he'd be quite a force. His speed and agility from being a ninja would give him an edge in battles on ships or islands. He could easily jump between masts or dodge cannonballs.
Well, hypnosis could be integrated as a new form of Quincy or Hollow power. For example, a Quincy could use hypnosis through their arrows, making the enemy see things like lemon - shaped distractions before attacking. This would add a new layer of strategy to battles in the Bleach world.