Well, Harry Potter is the central figure for sure. However, it's possible that some characters who Harry has helped in the past but aren't as prominent in the original series could also become important in this fanfiction. For example, those students who Harry saved during the Battle of Hogwarts. They might feel a great debt to Harry and be involved in his plan. Also, characters from the wizarding community at large, such as the Weasley family members other than Ron, or some of the Ministry of Magic employees who Harry has had an impact on, could be part of the story.
In addition to Harry, Ron, and Hermione, other characters could play significant roles. For instance, Neville Longbottom might be a key character. He's always been a loyal friend to Harry, and Harry may call on him for help. Also, Luna Lovegood with her eccentric but often perceptive nature could be involved. There could also be some of the Hogwarts professors, like Professor McGonagall. She's always been a mentor to Harry, and if there are debts to be called in regarding Hogwarts, she would be a part of it.
Obviously, Harry Potter would be the main character as the title implies. But his friends like Ron Weasley and Hermione Granger are also very likely to be important characters. Since they've been through so much with Harry, they might be among those who are called upon to pay their debts, or they could help Harry in the process of calling in debts from others.
There could also be characters like Dumbledore, even if in spirit or through memories. His wisdom might have influenced Harry's understanding of life debts, and his past actions could be related to debts that Harry is now calling in. And then there are the characters who owe Harry their lives. This could include Neville, who Harry has saved on multiple occasions, and their relationship could be further explored in the context of the life debt.
Obviously, Harry Potter would be one of the main characters. He is the one calling in the life debts. There might also be the people who owe him life debts, like some of his friends who he has saved in the past, or even some unexpected characters from the wizarding world.
Well, obviously Harry Potter himself would be the central character. He has always been a fighter for what's right in the original series, so it makes sense for him to be the main character in a fanfiction about justice.
In this fanfiction, perhaps Harry Potter has reached a point where he realizes he's done a lot for others in the wizarding community. So, he starts calling in all the debts. It could involve his friends like Ron and Hermione, who he might call upon for special assistance. It might also include other characters he's helped over the years. This could lead to all sorts of interesting plot developments, such as new alliances being formed or old secrets being revealed as people try to fulfill their debts to Harry.
Obviously, Harry Potter himself is the central character. Others could include Ron and Hermione, who have been by his side through many life - threatening situations and might also be in debt to him in some way, for example, if Harry saved them from a particular dark spell during a battle. Also, Neville Longbottom could be involved as Harry saved him from Voldemort during the Battle of Hogwarts.
Hermione Granger might also be a common character in such fanfictions. Given her intelligence and the times she has been in dangerous situations, there could be scenarios where someone owes her a life debt. For instance, a character she saved from a dark wizard might then be bound by a life debt to her, and their relationship could be explored in the fanfiction.
In addition to Luffy and Garp, other characters could also play important roles. For example, some of Luffy's crewmates like Zoro or Nami might be present when Luffy calls Garp. They could add their own perspectives and reactions. Also, there could be some marines around Garp when he receives the call, and their reactions to Garp's decision to go to Luffy could also be part of the story.
The main characters would surely include Harry Potter. He's the center of the story as he is the one with the Veela aspect. Ginny Weasley could also be a major character. If Harry is a Veela, it would change their relationship dynamics. Additionally, Dumbledore might play a significant role as he would be guiding Harry through this new discovery and helping him understand and control his Veela powers.
In this kind of fanfiction, Neville Longbottom could also emerge as a key character. He has shown great courage and growth throughout the Harry Potter series. When Hera enters the picture, Neville could be the one who has an unexpected connection with her. Maybe his family's long - forgotten magical heritage has some link to the Greek mythology that Hera represents. And then there are the Death Eaters. If the story is set during the darker times in the wizarding world, the Death Eaters might see Hera as a new threat or a potential ally, making them important characters in the fanfiction as well.
Obviously, Harry Potter would be one of the main characters. He's the central figure in the original series. And Ophis, as the other part of the fanfiction's title, would also be a main character. Her unique abilities and personality would play a big role. Hermione and Ron could also be important as they are Harry's closest friends and would be involved in any new adventures that come about due to Ophis's presence.