There could be original characters created specifically for this fanfic that are main characters. For instance, a skilled female ninja who is an expert in espionage and has her own motives and backstory. She could play a crucial role in the operations of the spy network, perhaps leading a team or being in charge of a particular area of intelligence gathering.
Well, Naruto himself might be one of the main characters. He could be using his ninja skills in a different way as part of the spy network.
Maybe there's a plotline where the spy network has to infiltrate a powerful enemy organization. They would need to use their unique skills and intelligence to overcome various obstacles and security measures.
The Shangjing spy network was handed over to Guo Baokun. After Fan Xian and the oil shop manager exchanged secret signals, the manager led Fan Xian into the rear courtyard and spread the conversation between him and the empress dowager. Fan Xian promised the shopkeeper that if the mission was successful, he would arrange for the shopkeeper to return to the Qing Kingdom to reunite with his family. The Shangjing intelligence network would be taken over by Guo Baokun. The shopkeeper did not receive such an order, but Fan Xian showed his commissioner's waist token and clearly stated that Guo Baokun was his direct subordinate. Therefore, the shopkeeper had no choice but to agree to bring Guo Baokun to meet the secret agent in Shangjing.
One of the key members could be Hinata. Her Byakugan ability allows her to see long distances and detect hidden enemies. This makes her great for gathering intelligence. Another might be Kiba with Akamaru. Their sense of smell can be used to track people and detect any strange scents that might indicate a threat or something unusual going on. Also, Sai could be in the network. His calm and calculating nature, along with his artistic abilities which could be used for coded messages, would be very useful.
Sasuke could be a good main character. He has the skills and the motivation. He's always been on a quest for power and knowledge, which could easily be tied into a spying storyline. He could be spying on other villages to gain an edge for Konoha or for his own personal vendetta.
In the spy vs spy game story, the most important characters are the two spies. They are both very secretive and have their own motives. They are constantly at odds with each other, and their actions drive the whole story forward. There may be other minor characters like informants or handlers, but the two spies are the focus.
I'm not entirely sure as 'lemon' in fanfiction often refers to something with adult or sexual content which is not appropriate to discuss in detail. But generally, a 'Naruto spy network' in fanfiction might be about a secret network of spies within the Naruto universe, perhaps involved in political intrigue, uncovering secrets of different ninja clans or villages.
Obviously, Naruto is the main character. He is the one who becomes this 'god - like' figure in the fanfic. But there are also other important characters like Sasuke. Sasuke might play a role in either supporting Naruto's new power or being in conflict with him because of it.
I'm not sure specifically as it depends on the particular spy camp novel. But usually there are trainees, instructors, and maybe some villainous spies.
In the 'spy classroom novel', the main characters are likely to be the trainees in the spy classroom. Some may be the best in combat, some might be excellent at decrypting codes. There could also be a teacher or instructor figure who guides them through their training and missions. These characters interact with each other, and their relationships play an important role in the story.
One of the main characters is often a resourceful spy who has to navigate through a world of danger and deception.