One possible plot development could be Naruto learning to master Samehada's unique abilities. Since Samehada can absorb chakra, Naruto might figure out a way to use this to his advantage in battles, like redirecting the absorbed chakra against his enemies.
The idea is cool because it can open up new storylines. For example, Naruto could go on adventures to discover more about Samehada's origin. This could lead him to new places and introduce him to new characters that he wouldn't have interacted with otherwise. It also adds a new layer to the Naruto universe in terms of weaponry and power - ups.
In some fanfictions, Naruto might gain the ability to absorb Samehada through a special encounter. Maybe he discovers an ancient jutsu that allows him to connect with Samehada on a spiritual level and absorb its power.
Perhaps Naruto has a different fighting style that Samehada finds more appealing. Naruto is known for his unpredictable and energetic combat, and Samehada might be drawn to that. It could also be that Naruto has a certain charisma or willpower that Samehada responds to on a more instinctual level.
In the fanfiction, it could be that Kisame gives Naruto Samehada as part of a deal. Maybe Naruto has to do something for Kisame in return. Naruto might struggle with the idea of making a deal with an Akatsuki member but decides it's worth it for the power of Samehada. Once he has it, he might face opposition from his friends and village elders who are suspicious of his new weapon and the way he obtained it.
Well, it could be about Samehada being overlooked in the Naruto universe. Maybe it's not being used to its full potential. For example, it might be that no one realizes its unique abilities aside from just being a weapon. Or perhaps it's being misused or underutilized by its owners.
Well, in 'naruto meets samehada fanfiction', Naruto could potentially have a fight with the wielder of Samehada. During the battle, he might discover some new aspects of his own powers as he tries to counter Samehada's ability to absorb chakra. And it could also lead to an unexpected alliance if they face a common enemy.
One consequence could be a change in his fighting style. With Samehada's absorption ability, Naruto could start using more defensive and counter - attacking strategies. He might be able to absorb an opponent's chakra - based attacks and then use that energy against them. Also, his relationship with his friends and allies could be affected. They might be a bit wary of his new power at first, but as they see Naruto using it for good, they would come to accept it.
It could be Samehada itself. Since the story is about it being neglected, it makes sense for it to be the main focus. It could have its own 'voice' and thoughts as it tries to deal with the situation.
First, you need to understand the characters well. Know their personalities, powers, and backstories from both Naruto and Fairy Tail. For example, Samehada has its unique characteristics in Naruto, and you need to incorporate that into the story in a logical way when combining it with Fairy Tail elements.