Well, it varies in different fanfictions. Some have Harry at 12, while others might make him 13 or even 14. It depends on the author's imagination and the plot they want to create.
In most fanfictions, Harry was around 13 years old when Sirius broke out of Azkaban.
The age of Harry when Sirius broke out of Azkaban in fanfiction can be quite diverse. Some authors stick closely to the canon age of around 13, but others might tweak it to add more drama or to suit their unique storylines.
It varies in different fanfictions. Some have Harry at 12, while others might depict him as 14 when this event occurs. It depends on the author's imagination and the story's plot.
One major challenge is the Dementors. They are extremely dangerous and can suck out a person's soul. Harry has to find a way to either avoid them or defeat them. Another challenge could be the security measures in Azkaban. There might be magical locks, guards, and other barriers that he needs to overcome.
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.
One possibility is that their meeting is a vision or a dream - like encounter. Harry could be drawn into Azkaban in his sleep or through a magical object. During this encounter, Sirius could give Harry advice on how to deal with the upcoming challenges at Hogwarts. He might warn Harry about certain people who can't be trusted and offer his insights on the growing dark forces.
Obviously, Harry and Sirius are the main characters. Harry is the one trying to break Sirius out, and Sirius is the one being broken out.
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.
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.
In some fanfictions, Harry might use powerful magic he's learned secretly. For example, he could discover a new spell that can break the Azkaban's defenses. He then sneaks into Azkaban, locates Sirius, and uses this spell to free him from his cell. Maybe he also has to fight off some Dementors on the way out.
One idea could be that Sirius Black's daughter, who has been hidden away all this time, discovers her true identity while trying to break into Azkaban to clear her father's name. She could have some unique magical abilities that help her in this dangerous quest.
Harry might be initially shocked. He could feel a mix of sadness and a sense of responsibility. After all, Sirius was like a father figure to him.