It could be Sirius Black. Since he has his own experience with Azkaban, he might know some secrets about the place. He could return in some form within the fanfiction and assist Harry in his escape, maybe by leading him through some hidden tunnels or using some special skills he developed during his time in prison.
Maybe he uses some powerful magic spells that he has learned secretly. For example, the Patronus charm could be used to fend off the Dementors which are the main guards in Azkaban. He might also get some unexpected help from his friends or some mysterious characters within the fanfiction world.
Well, perhaps he uses some powerful magic he's learned secretly. Maybe he has help from unexpected allies, like a magical creature that can bypass the prison's defenses.
Perhaps Voldemort has some inside help. He could have bribed or threatened one of the guards or even a Ministry official who has access to Azkaban. This person could then help him get in and break Harry out. Or he might have found a secret passage into Azkaban that the Ministry doesn't even know about, and he uses that to his advantage.
One reason could be that Voldemort wants to use Harry for his own gain. Maybe he thinks he can turn Harry to the dark side and use his power for some grand evil plan. He might believe that with Harry on his side, he can finally defeat all his enemies and rule the wizarding world completely.
One interesting plot point could be how Harry devises the plan to break Sirius out. Maybe he uses his invisibility cloak and some clever spells. Another could be the reactions of the other characters when they find out, like Hermione's concerns about the legality and consequences.
Harry Potter and the Prisoner of Azkaban was a fantasy novel written by K Rowling in England. It told the story of Harry Potter's parents being killed by the evil dark wizard Voldemort. After being adopted by an orphanage, Harry studied magic at Hogwarts School of Witchcraft and Wizardry and defeated Voldemort with his good friend Hermione.
In the fanfiction, the female Harry Potter might be sent to Azkaban as part of a plot by Voldemort to get rid of her. While in Azkaban, she discovers a hidden power within herself. It could be related to her connection with her mother or some ancient magic. She then starts to influence the other inmates with her positive energy, and they start to believe in her as a symbol of hope against Voldemort.
Harry Potter: Prisoner of Azkaban
Chapter 1:
Harry Potter and his friends arrive at Hogwarts, but they soon discover that they are not the only students of magic. A black cat appeared in their classroom and told them that an evil wizard was trying to sneak into the school. His name was Voldemort. Harry and his friends decided to help Voldemort catch him, but they soon discovered that Voldemort was very powerful and that they had to make many difficult decisions to defeat him.
Chapter 2:
Harry and his friends met a mysterious girl in their search for Voldemort. Her name was Bellatrix Lestrand. She told Harry about Voldemort's past and secrets, which made Harry even more worried that Voldemort might use Dark Magic against them.
Chapter 3:
Harry and his friends had finally discovered Voldemort's true hiding place, but he was surrounded by Voldemort's followers. Harry and his friends had to figure out a way to escape Voldemort's control and finally defeat Voldemort's followers.
Chapter 4:
Harry and his friends decided to leave Hogwarts to find Voldemort's other followers. They had gone through many difficult journeys but in the end they had managed to find Voldemort's followers and defeat them.
Chapter 5:
Harry and his friends finally returned to Hogwarts, but they found that Voldemort had regained his power. Harry and his friends had to make the difficult decision again about how best to deal with Voldemort's threat and protect the Wizarding world from him.