Well, Naruto is a given. Then, there may be an elf with healing powers who becomes an important part of Naruto's life in the fanfiction. There could also be an elf archer who is initially distrustful of Naruto but later warms up to him. And in the harem context, these elf characters are all vying for Naruto's attention in different ways, whether through their skills, their kindness, or their unique cultural knowledge.
Naruto is the key protagonist without a doubt. The Kyuubi, being an integral part of Naruto's power and character, is also prominent. As for the harem, it often consists of various female characters from the Naruto series. For instance, Ino could be one of them. These characters are usually there to form the romantic relationships with Naruto, adding different flavors to the story depending on their personalities and their individual relationships with Naruto.
Obviously Naruto is one of the main characters. And then usually some of the female characters like Sakura, Hinata, and Ino are often part of the harem that is being neglected. They are the ones who would typically have some sort of romantic feelings for Naruto in these fanfictions.
Main characters in naruto demon harem fanfic are Naruto, who is in the middle of all the action. Female characters such as Temari from the Sand Village might also be included. And the demon, which is what makes it a 'demon harem' fanfic. The demon might have its own motives and goals, which often clash with Naruto's. The female characters are caught in between, having their own feelings for Naruto and being affected by the presence of the demon. This complex web of relationships is what drives the story forward.
Well, Naruto is obviously one of the main characters. And then, there are the female versions of the Kyuubi. These could be different interpretations of the Kyuubi's power or different manifestations of the Kyuubi in a female form. They are central to the harem aspect of the fanfiction.
Well, Naruto is obviously one of the main characters. He brings his own set of skills, personality, and his journey from the original Naruto series into this fanfiction. Tsume is another key character, with her unique wolf - like traits and her own backstory that can be explored in relation to Naruto and the harem concept.
Obviously Naruto is one of the main characters. And then there are usually some of the female characters from the Naruto series like Sakura, Hinata, and maybe even some of the female ninja from other villages. They are often part of the harem that revolves around Naruto.
Tsukune is of course one of the main characters. He is often the center of the story around which the harem revolves. Then there are usually female characters like Moka, Kurumu, and Yukari. Moka can be both sweet and strong, Kurumu is flirty and confident, and Yukari is cute and mischievous.
Well, of course, Kiba is the central character. Then, there are often characters like Hinata who might be part of the harem. Her gentle nature can create interesting dynamics with Kiba.
The main characters are often Naruto, as he is the focus of the mecha concept. Shikamaru could also be a main character in this type of fanfiction. He would be the strategist, trying to figure out how to best utilize the mecha Naruto in battles. Additionally, Orochimaru might be a character in some cases. He could be interested in stealing the technology of the mecha for his own evil purposes or trying to manipulate Naruto through it.
Obviously, Naruto and Matsuri are main characters. Naruto, with his energetic and determined personality, often drives the story forward. Matsuri, being from Suna, brings a different perspective to the story. Sometimes, other characters like Sakura or Kakashi might also make an appearance to add more depth to the plot.