There could be a new character, a prison guard who befriends Harry. This guard could have a mysterious past and some unique abilities. He could help Harry navigate the complex politics and power struggles within Azkaban, and their friendship could be a key element in the story.
Harry Potter himself is of course very memorable in this fanfiction. His growth and development as the 'King of Azkaban' are central to the story. He might display new traits like increased determination and a darker side due to the harsh environment of Azkaban.
The Dementors might be even more menacing in this fanfiction. They could be portrayed in a more complex way, not just as mindless creatures. Maybe there's a Dementor leader that Harry has to confront, and this Dementor has its own motives and plans which add depth to the story.
Harry Potter himself is of course very common. He's usually the central figure in these fanfictions. Hermione Granger is also often included as she is Harry's friend and a brilliant witch. Ron Weasley too, as he's part of the trio. Sirius Black might also be a common character since he has a connection to Azkaban.
Sirius Black is often very popular. Since he's been freed from Azkaban, he brings a lot of mystery and a connection to Harry's past. Harry himself remains a central figure, of course. His growth and development after the events of Azkaban are always interesting to explore. Hermione is also popular as she continues to be the brains of the group, coming up with clever plans and solutions.
One popular original character is often a new student who has some special ability related to divination. This character can add new elements to the story, like predicting things about Sirius Black that no one else can.
Harry Potter himself is of course very memorable. He is the main character who has to face the great evil of Voldemort and has grown from an orphan boy to a powerful wizard throughout the series.
Some fanfics introduce a new character, a seer who can see not just the future but also alternate timelines. This character is unique as they can provide insights that no one else can, and often their visions drive the plot forward in unexpected ways.
Obviously, the child is one of the main characters. There might also be some prison guards who play important roles, either as antagonists or those who gradually change their views towards the child. And perhaps some other inmates who interact with the child could also be considered main characters.
There could also be new characters introduced specifically for this fanfiction. Maybe there's a vampire hunter who comes to Hogwarts thinking the vampire is a threat. This character would add a new layer of conflict and intrigue. Additionally, the teachers at Hogwarts, like Dumbledore, would still play significant roles as they try to maintain order in the school while dealing with this new and rather unusual situation.
Well, Harry Potter himself is obviously a very memorable character in this fanfiction as he is the central figure. His journey of walking the earth and the new experiences he has make him stand out.
One character that can be really memorable in 'Harry Potter and the Seven Horcruxes Fanfiction' is Luna Lovegood. Her unique perspective and strange yet often accurate insights can play a big role in the search for the horcruxes. She might be the one to figure out the true nature of a particularly tricky horcrux. Another could be Draco Malfoy. In some fanfictions, he could be forced to cooperate with Harry and his friends in the hunt for the horcruxes due to some unexpected circumstances, and his internal struggle between his family's values and doing the right thing can make him a very interesting and memorable character.
A new character created specifically for the fanfiction could be really memorable. Say, a young witch from a far - off land who has a unique magical ability that no one has seen before. She could be both a competitor and an ally to Harry, with her own backstory and motives that make her stand out.