Sasuke could be a rival. He's always been highly skilled and competitive. His Sharingan could potentially see through some of the henge master's henges, creating a constant challenge for the henge master to come up with more advanced henges.
The Solid Henge could be different in that it has a physical mass and durability. Regular henge is mainly for illusionary transformation, but the Solid Henge in fanfiction could be used to create actual objects that can be interacted with. For example, Naruto could create a solid bridge over a chasm instead of just the illusion of one.
One possible fanfiction idea could be Naruto using his henge technique to transform into someone wearing a really cool swimsuit. Maybe he does it for a mission at a beach resort where he has to blend in with the tourists. He could transform into a famous surfer and use his skills to gather information.
In a Naruto physical henge fanfic, the concept of physical henge can be a great way for character development. Imagine a character who is afraid of heights. They could use the physical henge to transform into a bird and face their fear. Through this experience, they could gain courage and self - confidence. Another way is that a character could henge into an older version of themselves to see how they might develop in the future. This can give them insights into their goals and what they need to do to achieve them. Moreover, characters can use henges to understand different cultures or species within the Naruto world, which broadens their perspective and helps in their development.
A 'Solar - Flare Rasengan'. Naruto could combine his wind - style chakra with some kind of solar - based energy he discovers. This jutsu would be like a super - charged Rasengan that emits a blinding light as well as powerful wind - based damage.
There could be a jutsu that allows for instant teleportation across long distances. This jutsu might be a new discovery in the fanfiction world, perhaps created by a character who has been experimenting with space - time ninjutsu. They might use it to quickly get in and out of battles or reach far - off places in a blink.
Well, Naruto could learn more about empathy. By being in Inari's form, he experiences life from Inari's perspective. This might make him more sensitive to the feelings of others who are not as confident or strong as he is.
He might also get help from his friends. For instance, Sasuke could sense that something is wrong with Naruto. With his Sharingan, Sasuke might be able to see through the henge and then use his own powers to help Naruto break free. Or Sakura could use her medical ninjutsu knowledge to somehow counter the effects of the henge on Naruto.
It could be a new form of Rasengan. Maybe Naruto discovers a way to combine different elements with the Rasengan more effectively, like adding lightning to it for a more powerful and faster attack.
One possible fanfiction could be that Naruto henge into a swimsuit as a prank. He might transform into a ridiculous swimsuit -covered version of himself to make his friends laugh. For example, he could turn into a swimsuit with a huge fish pattern all over it and start acting like a goofy mermaid in front of Sasuke and Sakura, just to break the tense mood during a training session.