His relationship with Sasuke might become more competitive. If Naruto awakens a powerful kekkei genkai, Sasuke, who is always striving to be stronger, would see Naruto as an even greater rival. This could lead to more intense training sessions between them and also some tension in their friendship.
It could be a water - based kekkei genkai. Since the Wave arc has a lot to do with water, it would make sense for Naruto to awaken a kekkei genkai related to water. This could give him an edge in battles, especially in the Wave region where water is abundant.
It might isolate him. If his Kekkei Genkai is very powerful and different, others could be afraid of him. For example, if he has the power to see into people's souls, it could make people uncomfortable and they might avoid him.
His relationship with his teachers could change too. Kakashi might have to develop new training methods for Naruto to master this kekkei genkai. Iruka would be very supportive as always, but also a bit worried that Naruto might attract more dangerous enemies with this new power. And with the other ninja villages, they might view Naruto with more caution or respect depending on how powerful his kekkei genkai is.
Well, in some fanfictions, Naruto might obtain all kekkei genkai through some sort of ancient and powerful jutsu. Maybe he discovers a hidden scroll or meets a mysterious sage who imparts this power to him.
Kekkei genkai can make a character stand out. For instance, if a character has a rare and powerful kekkei genkai, others in the harem might be initially attracted out of admiration for their power. It can be a starting point for relationships.
Well, it could be something like a fire - based kekkei genkai that allows Naruto to control blue - flame fire which is hotter than normal fire. This would give him an edge in battles and also a new look to his fighting style.
In fanfiction, if the Uzumaki's kekkei genkai is a sealing - based one, clans with valuable secrets or jutsu might be cautious around them. They might be worried that the Uzumaki could seal away their important techniques. On the other hand, clans with a need for better sealing might approach the Uzumaki for help, leading to various types of relationships, from friendly cooperation to tense negotiations.
In fanfiction, it could be due to some special training. Maybe he meets a super powerful mentor who has knowledge of all kekkei genkai and teaches him the secrets. Or perhaps he discovers some ancient jutsu that unlocks this ability within him.
One interesting plot could be Naruto awakening a unique kekkei genkai that gives him the ability to control time. This would completely change the dynamics of his battles and how he approaches his missions. For example, he could freeze time to avoid attacks or rewind time to correct mistakes during a fight.
There's also the possibility that the main antagonist is a group of ninja from a rival village. They fear Naruto's new power and form an alliance to take him down. They might have spies within Naruto's village trying to gather information about his kekkei genkai so they can develop counter - measures and ultimately defeat him.