One idea could be a crossover where Naruto characters visit the world of Maken Ki. For example, Naruto and his friends could be on a mission that accidentally transports them to the Maken Ki universe. They might have to team up with the Maken Ki characters to face a common enemy that threatens both worlds.
Naruto could use Ki to enhance his sensory abilities. In the Naruto universe, he already has good sensory skills with his chakra. But by adding Ki into the mix, he could expand his range of detection even further. He could sense enemies from much greater distances or even detect hidden traps or secrets in the environment around him.
One effect is increased power. Naruto can become extremely strong and defeat powerful foes more easily. For example, he could take on enemies that were previously unbeatable in the original Naruto story.
Another theme is the impact on relationships. When Naruto has god ki, his friends might view him differently. Some might be in awe, while others could be a bit jealous. And his enemies will surely change their approach to him. Also, the concept of destiny often plays a role. Is Naruto meant to have this god ki for a greater purpose in the Naruto universe? The fic may explore this as well.
In some fanfictions, Naruto might be able to use Ki by undergoing special training. Maybe he meets a mentor who teaches him the ways of Ki manipulation. This mentor could be from a different realm or have a unique connection to Naruto's own chakra system, and through intense practice and spiritual growth, Naruto gradually masters the use of Ki.
Yes, in some fanfictions Naruto can be depicted as having God Ki. Writers often like to give their own unique twists to characters, and giving Naruto God Ki is a way to enhance his power and make him even more extraordinary in the fan - created storylines.
One interesting Naruto ki user fanfiction could be about a new character with a unique Ki ability who teams up with Naruto. They might go on a journey to discover the origin of this Ki power and how it relates to the Ninja world's chakra. This could lead to new adventures and battles, as they face off against enemies who are also intrigued by this new power.
Naruto's advantage with Ki would be the ability to access a different type of energy source. This could potentially allow him to break through new barriers in his power development. Tenten could use Ki to make her weapons more versatile. For example, she could change the shape or trajectory of her weapons mid - flight using Ki. Also, both of them could use Ki to better defend against attacks. Ki could form a protective shield around them, which is something new compared to their normal defenses in the original series.
In a fanfiction, a Maken Ki object or power that was thought to be a great source of good turns out to be corrupted. It starts causing chaos in both the Naruto and Maken Ki worlds. The characters then have to figure out how to stop it without destroying it completely, as it still has the potential to be a force for good if they can cleanse it.
One interesting plot idea could be the main character mastering a new and unique form of chakra control. For example, being able to combine different elemental chakra in ways not seen before in the Naruto universe.