He might want to protect himself. If others know how smart he is, he could become a target. Enemies might see him as a greater threat and go after him more aggressively.
He might use simple language on purpose. For example, he could pretend to be confused about things he actually understands well. He may also make silly mistakes intentionally to give the impression that he's not as smart as he really is.
Yes. In some fanfictions, Naruto might show his intelligence by outwitting his enemies in battles. For example, instead of relying solely on brute force like in the original series sometimes, he could use clever strategies to defeat opponents who are stronger physically. He may analyze their fighting patterns quickly and come up with unique plans on the spot.
One possible plot could be Naruto and Hinata working together in the intelligence agency to stop a group of rogue ninjas who are stealing secret jutsu. Naruto could use his combat skills and Hinata her Byakugan's observational abilities to gather intelligence and take on the enemies.
In these fanfictions, Naruto's smartness also shows in his interpersonal relationships. He's able to read people's emotions and intentions accurately. When dealing with a new character, he can quickly assess whether they are trustworthy or have hidden motives. This emotional intelligence helps him form alliances and avoid being betrayed, which is crucial in the dangerous world of ninja. He can also use this understanding to manipulate situations to his advantage when necessary.
In the fanfiction, Naruto's strong sense of justice and his never - give - up attitude could drive the agency's efforts to uncover the truth. He would be the one pushing forward when they face difficult cases. Hinata, with her family's knowledge and her own skills, could be the one who provides in - depth analysis of the intelligence. Her Byakugan not only helps in seeing the physical layout but also in detecting any hidden chakra - based traps or devices that might be relevant to the intelligence operations.
In the fanfiction, Naruto's intelligence could be demonstrated in his study of ancient ninja lore. He may be able to uncover secrets and use that knowledge to his advantage. In the original Naruto, while he does learn things, it's not as emphasized as in the fanfiction. Also, in the fanfiction, Naruto could use his intelligence to predict his enemies' moves more accurately, whereas in the original he might rely more on his instincts and the help of his friends.
One possibility could be an OC who is a shepherd of the intelligence sheep. This OC could have unique jutsu related to mind - control or knowledge - gathering, which they use to lead their sheep followers. The sheep could be like manifestations of hidden knowledge in the Naruto world.
The OC could be found as a child by the intelligence sheep. Maybe the OC was lost in a forest and the sheep, sensing the OC's potential, took them in. As the OC grew up among the sheep, they learned the ways of the Naruto world from the sheep's collective intelligence. This experience could shape the OC's values and abilities, for example, giving them an uncanny ability to read people's intentions, similar to how sheep can sense danger in the wild.
Naruto could be the fearless field agent, always ready to jump into action and take on any danger head - on. Hinata might be the intelligence analyst, using her Byakugan to carefully observe and analyze all the information they gather.