One possible plot could be that a powerful villain tries to create a new Buu - like being using Naruto's chakra. But instead of creating a new Buu, Naruto is reincarnated as a hybrid of himself and Buu. This would lead to a lot of internal struggle for Naruto. He would have to deal with Buu's instincts while still trying to protect his village and friends. His friends might be initially scared of him, but over time they come to understand and accept this new Naruto.
It could be someone who wants to use Naruto's new Buu - like powers for their own evil purposes. Maybe an old enemy who realizes that Naruto in this new form is a huge threat to their plans. For instance, Orochimaru might see this as an opportunity to gain even more power and try to control Naruto - as - Buu.
One possible fanfiction could involve Naruto being transported to the Dragon Ball universe where he meets Female Majin Buu. Maybe they start as adversaries at first. Naruto, with his ninja skills, tries to fight her. But then they realize they have some common ground in their love for food. And they could end up teaming up against a greater threat in the Dragon Ball world.
One unique feature is the combination of two very different universes. Naruto's world of ninjas with its complex jutsu system and Maji Buu's world which might have its own set of rules and powers. It allows for really creative storytelling.
His usual friends like Sasuke and Sakura could still be his allies. Despite his new connection to Majin Buu, they might stand by him because of their long - standing friendship. Kakashi too could be an ally, guiding Naruto as he did before, but now also helping him understand and control his Buu - like powers.
The Naruto - Kid Buu fusion in fanfiction could be depicted as a being with a unique fashion sense. Since Naruto often wears orange and Kid Buu is mostly pink, the fused form might have a combination of those colors in its clothing or body markings. In terms of abilities, it could be shown as having the speed of Naruto when he uses his chakra to enhance his movement, combined with Kid Buu's ability to transform parts of his body into weapons. For example, the fused form could create Rasengan - like attacks from its hands which are also able to stretch like Kid Buu's arms.
In a fanfiction where Naruto fuses with Kid Buu, it could result in a very powerful and unpredictable being. Naruto's positive energy and strong will might conflict with Kid Buu's chaotic and destructive nature at first. But perhaps over time, Naruto could influence the fused form to use its power for good. For example, the fused being might have Naruto's skills like the Rasengan combined with Kid Buu's ability to regenerate and his raw power. It could also lead to some really interesting battles against other powerful characters in the Naruto and Dragon Ball universes combined.
Well, it could be about Naruto having the unique powers of Majin Buu. Maybe he'd have the ability to regenerate like Buu. And his personality might change a bit, being more unpredictable. He could use Buu's techniques in battles against his enemies in the Naruto world.
In a fanfiction where Naruto fuses with Majin Buu, there could be some really wild power combinations. Naruto's chakra and Buu's unique abilities like regeneration and absorption might create a super - powerful being. For example, Naruto could potentially use his Rasengan with Buu's stretchy body to create new and unpredictable attacks.
Another concept could be that a part of Majin Buu's essence gets mixed with Naruto's chakra during an experiment gone wrong. Naruto now has to control this new power within him while also keeping his own identity, all the while dealing with the suspicion of his friends and the potential danger it poses to the village.