Minato could be a common character. Since he was Kushina's husband in the original story, his presence might add some interesting dynamics to the harem scenario. Another could be Jiraiya. His connection to Naruto and his reputation as a bit of a ladies' man could make for an interesting addition to the story.
There might also be characters like Kakashi. His cool and mysterious demeanor could play into the harem story. He could be a mentor figure to Naruto in dealing with the harem situation. And Tsunade might also be included, perhaps as a powerful figure who has an influence on the relationships within the harem.
Often, characters like Sakura and Hinata might be included. Sakura could be jealous of the harem situation around Naruto and Kushina, which could lead to some drama. Hinata, on the other hand, might be more understanding and could potentially be part of the harem herself, adding a new layer of relationships to the fanfiction.
Minato might be a common character. Since he is Kushina's husband in the original story, his presence can add an interesting dynamic. Also, Jiraiya could be there. He was Naruto's mentor and his interactions with the harem situation could be quite humorous.
Iruka could be one of the characters. He has always been important to Naruto, and he might try to help Naruto or at least be concerned about his exile. Kakashi could also appear. He has a connection to Naruto and might be conflicted about the situation. And then there are Naruto's friends like Sasuke and Sakura. Sasuke might understand Naruto's feeling of being an outcast more than others, and Sakura could be torn between her loyalty to the village and her friendship with Naruto.
Another theme is often the power dynamics. Kushina has her own strength, and in the harem situation, how her power and influence interact with the other characters in the harem is explored. For example, she might use her skills to protect those in her harem or gain more influence within the group. It also delves into how the other characters' powers play into the overall dynamic of the harem. There can be rivalries and alliances based on power levels.
Obviously, Naruto is a central character. Kushina herself often appears, either in flashbacks or in some magical - like resurrected form. Minato, Naruto's father, is also common as he is closely related to Kushina. Then there are Naruto's friends like Sasuke and Sakura. They might play different roles, for example, Sasuke could be more involved in helping Naruto understand his mother's side of the family.
Other characters like Kakashi or Jiraiya could potentially be part of the harem in some fanfictions. Their unique personalities would bring different elements to the story. Kakashi's cool and mysterious nature or Jiraiya's more carefree and perceptive self could interact with Kushina and the rest of the harem in various ways.
Sakura could be quite intriguing. She has her own relationship with Naruto and Sasuke in the original story. In a harem fanfiction, she could be a bit jealous or supportive of Naruto's new harem situation. Tsunade is also a possibility. As the Hokage, she could have a unique perspective on Naruto's harem. She might be concerned about how it affects his role in the village or she could see it as a positive thing for his growth.
Jiraiya could also be one of the main characters. He was Naruto's mentor and had a connection with Kushina's family. He could play a role in helping them adjust to the time travel and also use their knowledge to his advantage in some ways, like getting intel on future threats.
Another aspect could be that the fanfiction delves into how Kushina's presence affects Naruto's relationships with others. For instance, his relationship with Sasuke could be different. With a strong maternal figure in his life, Naruto might be more stable emotionally and be able to approach Sasuke in a more understanding way, which could potentially change the whole dynamic of their rivalry and friendship.
Minato is often paired with Kushina in these fanfictions. Their relationship was a significant part of the Naruto story, so many fanfictions expand on their love story. Another popular pairing is Kushina and Naruto. It could be a story where Kushina is brought back to life and gets to be a part of Naruto's life in a more direct way.
Obviously, Kushina herself would be a central character. Minato could also be involved, perhaps in a complex relationship triangle with Naruto and Kushina. Then there are other female ninjas like Tsunade. She might be intrigued by Naruto's time - traveling knowledge and get involved in the story. Sakura could also be a potential character. If she somehow gets dragged into the time travel, she might have her own role in the harem - like situation around Naruto.