He would be protective of the cat. Given his nature of always wanting to protect the weak, if any threats came towards the cat, Naruto would be the first to step in. He might also talk to the cat a lot, sharing his dreams and stories about his adventures, even if the cat couldn't understand his words.
The cat could have the ability to sense chakra. Just like how some animals in the Naruto world can detect danger or the presence of others through their natural instincts, Naruto's cat might be able to sense chakra levels, which could be helpful to Naruto in various situations.
In 'naruto as a cat fanfiction', Jiraiya could be an interesting character to interact with Naruto as a cat. He might see some potential in this cat - form Naruto for some new ninja techniques. The Akatsuki members could also interact with Naruto as a cat. For example, Itachi might sense something unusual about this cat when he passes through the village. And Konohamaru could be another character. He would be really excited to have a cool cat friend, not knowing it's Naruto.
The cat could have the ability to turn invisible. This would be really useful in spying on enemies or sneaking into dangerous places. Naruto could use this to his advantage during missions.
In a fanfiction, a cat could be a messenger from another dimension. It comes to Naruto and Hinata, choosing them specifically. The cat leads them on an adventure to save the other dimension. Along the way, Naruto and Hinata's relationship blossoms as they rely on each other and face challenges together with the help of the cat.
The cat could make Naruto more approachable. His friends might be drawn to the cat and start spending more time with Naruto because of it. For example, Sakura might see Naruto's kindness towards the cat and start to view him in a new light, strengthening their friendship.
They could go on adventures in the forest outside the village. For example, they might encounter strange creatures that the cat's instincts help them avoid or deal with.
In 'Naruto is a cat' fanfiction, the relationships change in interesting ways. For example, his friends might treat him more protectively or find his cat - like behaviors endearing. Also, his enemies might underestimate him, which creates new plot opportunities.
Well, in a 'naruto is a cat faunus fanfiction', it could center around Naruto's interactions within the cat faunus community. Since Naruto is usually known for his energetic and somewhat goofy nature in the original series, as a cat faunus, he might get into all sorts of misadventures. He could be trying to prove himself as a capable 'ninja' despite the differences in his new form. It might also involve his relationships with other characters from the Naruto universe, who now have to view him in a whole new light as a cat faunus.
A third common theme is the idea of the underdog. Naruto was an underdog in his own ninja world, and the cat is often portrayed as an underdog as well. Together, they overcome challenges and prove that even the smallest or most overlooked can achieve great things. For instance, the cat might be a runt that Naruto helps to become strong, and in turn, the cat helps Naruto in unexpected ways.