He would probably face a lot of challenges at first. Since he's been neglected, he might not have the proper training to handle the Zanpakuto right away. But as he learns, he could start to gain respect from those who once neglected him. His new power would change the way people view him in the Naruto universe.
The Zanpakuto could also give Naruto a new sense of identity. He's always been the outcast in some ways in the Naruto story. But with this new weapon, he could form his own path. He might even attract new allies who are interested in his unique combination of Naruto - style powers and the Zanpakuto abilities.
At first, Naruto would be clumsy with it. He has no prior experience with Zanpakuto. But his determination would drive him to practice. He'd study how to hold it properly, how to swing it effectively. Maybe he'd even talk to it like he does with his friends, trying to understand its spirit if it has one.
Well, Naruto might use the Keyblade to gain power and respect. He could start training with it and show those who neglected him what he's capable of.
The zanpakuto might change Naruto's personality a bit. As he delves deeper into understanding and using it, he could become more in tune with the spiritual side of things, which is different from his usual ninja - based mindset. This could make him more solemn or more in touch with his inner self, much like how Ichigo in Bleach was affected by his zanpakuto.
In a 'naruto gets captured' fanfiction, he might be tortured for information. His captors could be after the secrets of his Nine - Tails chakra. They may try to use him as a bargaining chip against Konoha.
Well, Naruto could gain the ability to use Kamui and use it for various things. Maybe he'd use it to surprise his enemies in battle, suddenly disappearing and reappearing in unexpected places. He could also use it to rescue comrades who are in dangerous situations that are hard to reach normally.
One possibility is that Naruto discovers a new level of relaxation he didn't know before. He's always on the go as a ninja, so the massage might open his eyes to the importance of taking a break.
Imagine if the tanto was a gift from a mysterious stranger. This stranger could be an ally or an enemy in disguise. Naruto would be suspicious but also intrigued. As he tries to figure out the stranger's motives, he also has to deal with the tanto's unique abilities. Maybe the tanto can transform into different shapes, and Naruto has to learn how to control this transformation in the heat of battle.
In this type of fanfiction, Naruto could have a different attitude towards authority. As his parents are neglecting him, he might not have that natural respect for figures of power. He may question the village's system more. Also, his dreams of becoming Hokage could take on a new meaning. Instead of just seeking recognition, it could be a way for him to create a family - a village where no one is neglected like he was by his parents.
Perhaps they are a gift from a mysterious and powerful being who sees Naruto's potential. This being could be observing the Naruto - verse from afar and decides that Naruto is the perfect candidate to wield dual zanpakuto. The being may have their own reasons, like wanting to see how Naruto will use the powers of two zanpakuto to change the balance in his world.
Naruto could have a Zanpakuto with the ability to create illusions of hope. Given his character, it would make sense for his Zanpakuto to have an ability that gives his opponents a vision of a better future if they stop fighting. This would be a non - violent way of ending battles, which aligns with Naruto's ideology. Another possible ability could be to transform his chakra into a tangible form that can be used to either heal or boost the strength of his allies. It would be like his chakra is being channeled through the Zanpakuto in a more controlled and versatile way.