In canon, Harry grows up in England. If he lives in Canada from a young age, he won't have the same experiences at Hogwarts in England. For example, he might attend a different wizarding school in Canada, with different house systems and teaching methods.
In the original story, Harry is very much involved in the fight against Voldemort in England. But if he's in Canada from a young age, his role in the fight could be very different. He might be more on the sidelines, providing support from Canada, or he could be fighting a different kind of dark magic threat that is specific to Canada. His magical education and skills would also be shaped by the Canadian wizarding environment, which could be very different from what he would have learned in England.
In the canon, Harry has his moments of doubt and vulnerability. But in confident Harry Potter fanfiction, he's more self - assured. For instance, in canon, Harry might be hesitant to trust new people, but in fanfiction, a confident Harry could be more open - minded. This changes the flow of the story as he interacts differently with both friends and foes.
One possibility is that he discovers ancient Canadian magic that has been long forgotten. This could lead him on a journey to uncover the secrets of this magic. He might also have to face some challenges related to cultural differences between the wizarding world in Canada and that in other places. For example, different magical traditions and taboos. And as he grows up, he could become an ambassador of sorts between the Canadian wizarding community and the international magical community, sharing the unique aspects of Canadian magic with the rest of the world.
In canon, Harry and Narcissa have no such soul bond. So in the fanfiction, it's a completely new aspect. Canonically, Narcissa is mainly concerned with her family's well - being within the Death Eater regime. But in the fanfiction, the soul bond would force her to think beyond her family's usual allegiances. For Harry, in canon he is focused on defeating Voldemort and his Death Eaters, while in the fanfiction, this bond with Narcissa might make him see the other side in a different light, perhaps finding some redeeming qualities in those he once considered pure enemies.
Canon Harry Potter is often seen as a hero who follows the rules and values of the wizarding world. However, in dark godlike fanfiction, he may break the rules more freely. He could have powers that are not part of the normal magical repertoire in the books. His relationships with other characters can also change drastically. For instance, his friendship with Ron and Hermione might be strained as his new powers and 'dark' nature set him apart. He may also view the Ministry of Magic in a different light, perhaps as an obstacle to his new - found power and goals.
In old man Harry Potter fanfiction, one big difference from canon is his role. In the original books, he was a young hero, but in fanfics, as an old man, he often becomes a mentor figure. For example, in many fics, he teaches the new students at Hogwarts things he learned the hard way.
It differs from canon mainly in perspective. In canon, we follow Harry's journey mostly. But in 'stepping back' fanfiction, we might see the story from a side character's view. For example, we could see the Triwizard Tournament through Cedric Diggory's eyes. Also, the timeline can be altered. Canon has a set sequence of events, but fanfiction can change when certain things happen. For instance, if the Chamber of Secrets was opened earlier.
In canon, Harry has his fair share of hardships but not this kind of extreme abuse. In these fanfictions, the situations are much darker. Canon focuses more on the battle against Voldemort, while the fanfictions focus on Harry's personal and often very difficult experiences with abuse. Also, the relationships in canon are more positive overall compared to the strained and often negative ones in these fanfictions.
The plot in criminal Harry Potter fanfiction is different from canon as it delves into the seedy underbelly of the wizarding world. While canon mainly shows the school life at Hogwarts and the fight against Voldemort's tyranny, criminal fanfiction might introduce new criminal organizations or gangs that operate secretly. These could be made up of characters from different houses or even former Death Eaters and Order of the Phoenix members who have turned to a life of crime. This creates a much more complex and morally ambiguous plot compared to the relatively clear - cut plotlines in the original series.
His personality would be shaped by the strict religious environment. He'd likely be more respectful of authority figures, having been raised by nuns. In the wizarding world, this could mean he has a different relationship with teachers like Snape. He might also be more empathetic towards those who are ostracized, like the house - elves, because of the values instilled by the nuns about caring for the less fortunate. Moreover, he would be more accustomed to a simple life, so the grandeur of the wizarding world might both amaze and overwhelm him at the same time.
It often differs in the sense that it allows for more creative interpretations. Canon is quite fixed, but in a fanfic, the author can make Harry say things or have experiences that might not be in the original books. For example, he could have a different view on a particular spell or a character.