In many cases, the main protagonist from the original work is likely to be involved in '7th time loop fanfiction'. For instance, in a 'Harry Potter' - inspired fanfic of this kind, Harry Potter himself would be a popular choice. He has a rich backstory and a lot of potential for character development within the time - loop concept. Similarly, in a 'Star Wars' - related fanfic, characters like Luke Skywalker or Rey could be the ones in the time loop. Their existing storylines and powers make them interesting candidates to explore how they would react and change in a seventh time - loop scenario.
It really depends on the source material. For example, if it's based on a superhero franchise, it could be the main superhero like Superman or Batman. If it's a fantasy - based one, perhaps a wizard or a chosen hero from the original work. There's no one - size - fits - all answer as different fanfictions can be based on different universes and thus feature different popular characters.
Liara is another character that frequently shows up. Her knowledge of Prothean technology and history might be crucial in understanding and potentially stopping the time loop. She could be using her skills as a scientist and her connection to Shepard to figure out what's going on.
In most 'time loop Harry Potter fanfiction', Harry is front and center. His character development within the loop is usually the focus. But Hermione is a key figure too. She could be the one to discover the magical theory behind the time loop. For example, she might find a long - forgotten spell or potion that could be related to time manipulation. Ron, although sometimes overshadowed by Harry and Hermione, can bring in the element of friendship and loyalty. In some cases, characters from the Death Eaters side like Bellatrix Lestrange might be involved if the time loop is related to a major battle or a plot against Voldemort. Their presence can add more danger and complexity to the story.
Sansa Stark is frequently in these fanfictions. As someone who was a victim of Joffrey's cruelty, if he is in a time loop, Sansa might find herself in a different situation each time. Maybe in one loop Joffrey starts to treat her better, which would completely change her perspective and her own actions within the story. Also, Cersei Lannister could be involved. As Joffrey's mother, she would be very concerned about any changes in her son during the time loop and might try to interfere to keep things as she wants them.
Naruto could be often involved. Since he's Kakashi's student, he might be part of the events that keep repeating in the time loop. Kakashi could be trying to protect Naruto in different ways each time the loop occurs.
His companions like Amy Pond and Rory Williams are often involved. They are important as they have been with the 11th Doctor through many adventures and their reactions to his regeneration are crucial parts of the story.
Well, of course, Ichigo himself is the central character. But Rukia also often plays an important role. Since she was the one who initially transferred her powers to Ichigo, in the time - travel scenarios, she might be involved in different ways. Maybe Ichigo goes back in time to save her from some danger she faced in the past.
I don't know for sure since I don't have the details of this specific '7th time loop novel'. But usually, there would be a protagonist who is experiencing the time loop, and perhaps there could be a sidekick or a love interest who helps or hinders the protagonist's progress within the loop.
Sasuke is also a popular choice. Given his complex character and his quest for power, in a time - travel scenario, he could go back in time to gain more power or change the events that led to the downfall of his clan. Another character is Kakashi. His past and his relationship with Obito could be explored in a time - travel fanfiction. He could try to prevent Obito's fall to the dark side if he had the power to time - travel.
King might also be a character in time travel fanfiction. His search for his true identity could be further explored through time travel. He could go back to the time when his species was more prevalent in the Boiling Isles to learn about his origins, which would be an exciting adventure in the context of time travel fanfiction.
Often, the main protagonist is a very popular character in good time loop fanfiction. They are usually the ones driving the story forward, trying to figure out the loop and how to either escape or manipulate it. Another popular type of character could be the mentor figure. This character might have some knowledge about the time loop, whether from past experience or from some other source, and they help the protagonist on their journey.