Since I haven't read the 'Time Travel Team Seven Fanfiction', I can only guess. There could be a main character who is a brilliant scientist or inventor who is the mastermind behind the time travel concept. This character might be constantly tinkering with the time travel equipment to improve it or fix it. There could also be a young and curious character who is always eager to explore new time periods and learn about different cultures. And perhaps a wise old - timer type of character who has some prior knowledge or experience related to time travel that he or she imparts to the team.
Obviously, the main characters would be the members of Team 7, which include Naruto, Sasuke, and Sakura. Naruto, with his determination and never - give - up attitude, would be a key player in dealing with the challenges of the past. Sasuke, with his powerful ninja skills and complex personality, would also play an important role. And Sakura, who has grown into a strong kunoichi, would contribute with her medical and combat abilities.
Obviously, Kakashi is one of the main characters since it's about his time travel. Minato is also a central figure as he is part of Team Minato that Kakashi travels back to be with. And of course, the other members of Team Minato like Obito and Rin are likely to be important characters as well.
Well, Naruto would be the one to bring hope and his unique brand of optimism to the past. He could show the younger versions of characters how to be a better ninja. Sasuke, being the brooding and intelligent one, would analyze the situation of the past and figure out how to use their time - traveling advantage to the fullest. Sakura, she'd be a key player in both the medical and combat aspects. She could teach the past medics new techniques. And Kakashi, he's the experienced one. He'd be making sure the team doesn't make any rash decisions that could mess up the timeline further.
Obviously, the main members of Team Natsu like Natsu, Lucy, Gray, Erza, and Happy are always involved. They are the core of the group and any time travel adventure usually revolves around them.
In this fanfiction, an interesting concept is the cultural clashes they experience during time travel. Team Seven could land in a medieval society and have to adapt to the strict social hierarchies and different values. Or they could end up in a future society with very different moral and ethical standards. These cultural clashes would not only test their adaptability but also force them to re - evaluate their own beliefs and values.
Ban could be another one. He has his own backstory related to the sins and his immortality. He might time travel to find a way to break free from his immortality curse or to go back and correct a mistake he made when he was under the influence of one of the sins, like greed when he stole something important in the past.
Maybe an ancient and powerful ninja who was sealed away in the past and Team 7's time - traveling disrupts the seal. This ninja then sees Team 7 as a threat to his plans of ruling the world and becomes the antagonist.
There could also be characters from the past that become central to the story. For example, if they go back to the time of the First Hokage, Hashirama Senju could be a major character. Team 7 might interact with him, learn from him, or even have to work with or against him depending on the plot of the fanfiction.
Typically, the focus is on Naruto, Sasuke, and Sakura from Team 7. Naruto's never - give - up attitude is likely to be a driving force in trying to break the time loop. Sasuke's power and his complex personality add depth to the story. Sakura, on the other hand, with her skills as a ninja and her relationship with the other two, is an important part of the exploration of the time - loop concept in this fanfiction.
Obviously, Natsu Dragneel is one of the main characters. His impulsive nature often leads to interesting situations during time travel. Lucy Heartfilia is also important as she might use her celestial magic in unexpected ways in the different time periods. Gray Fullbuster, with his ice - magic, could be involved in battles against past or future enemies. And Erza Scarlet, with her strong combat skills and leadership, would play a crucial role in guiding the team through the challenges of time travel.