His friends might be in awe. After Ichigo meets his real Zanpakuto, his friends could be both amazed and a little bit intimidated by the new power he has. They would still support him, but there could be a new sense of respect and a bit of distance as they realize how much stronger he has become.
Well, Naruto's Zanpakuto might affect his performance in multiple ways. Firstly, it could change his fighting style. Instead of relying solely on his shadow clones and Rasengan, he might start using more sword - based techniques. This would catch his opponents off - guard as they are used to his usual moves. Secondly, if his Zanpakuto has some sort of elemental power, like being able to shoot fire or ice, it would expand his arsenal during the exams.
One possible plot twist could be that his heritage is linked to an enemy he thought was unrelated. So he has to reevaluate his views on the whole conflict.
He might learn about hidden magical talents in his family. For example, perhaps there were ancestors who could communicate with magical creatures in a unique way that was lost over time.
His fighting style would be more brute - force based. Instead of using all those ninja techniques in a strategic way, he'd just charge in and start slashing like Kenpachi.
If Luffy has a Zanpakuto in fanfiction, it could change his character development a great deal. Firstly, he'd have to adapt to a new type of power source. The Zanpakuto's power might be very different from his Devil Fruit power. He may become more cautious as he learns about the Zanpakuto's capabilities and how to control it. Secondly, his relationships with his crew could change. They might be curious about this new weapon and how it affects Luffy. This could lead to new interactions and discussions within the crew. And finally, in terms of his enemies, they would see him in a new light. They would need to strategize differently against a Luffy with a Zanpakuto, and this could also impact how Luffy views himself and his role as a pirate.
Well, he might gain new and powerful abilities. In the fanfiction world, meeting one's real Zanpakuto could be a turning point. Ichigo could unlock hidden powers that were previously unknown to him, which would make him even more formidable in battles against his enemies.
Ichigo might gain the ability to manipulate shadows with the Darkness Zanpakuto. He could use the shadows to hide, to attack from unexpected angles, or even to create illusions. This would give him a whole new set of tactical options in battles. He could also absorb the darkness around him to strengthen his attacks or heal himself, much like how he currently absorbs spiritual energy.
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.
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.