Ron Weasley can be there too. He could provide some comic relief and also be a friend to the new child. His loyalty and his family's unique place in the wizarding world can add interesting elements to the fanfiction.
Obviously, Harry Potter himself often makes an appearance. He could be a mentor or just a character that the new child of magic looks up to.
Often, Harry Potter himself is a common character. He might be exploring new aspects of water magic. Hermione is also likely to be involved as she loves to study and could be researching water - based spells. Ron could be there too, maybe a bit hesitant at first but getting into the adventure of water magic. And of course, there could be original characters created specifically for the fanfiction, like a young wizard from a family known for their water magic abilities who befriends Harry and the gang.
Harry Potter himself is often involved. Writers might explore how he could use the magic eye in different ways to solve mysteries or fight against the dark forces. Hermione would also be a common character. She could study the magic eye and try to understand its mechanics and magic better.
Well, Neville could be a significant character. He has come a long way since his Hogwarts days and could be a source of inspiration and support for the secret child. Ginny, as Harry's wife, is also very likely to be in these fanfictions. She could be a protective mother figure, or she might be involved in the decision to keep the child's identity a secret in the first place. And of course, there could be new characters created specifically for the fanfiction that interact with the secret child in various ways.
Hermione is often a common character. In these fanfictions, she might play a different role. For example, she could be the one to discover Harry's unique upbringing and help him understand how it makes him different from other wizards. Ron could also be there, and his friendship with Harry might develop in new ways. Maybe he's a bit more in awe of Harry's magic since he was raised by more powerful magic sources.
Well, of course, Harry Potter is common. But you'll also find Dumbledore in many fanfics related to this. He could be guiding the main character in their journey with the sword and magic. There are also fan-created characters, like a powerful witch from a far - off land who comes to Hogwarts because of the rumors of the magical sword. These characters add new dynamics to the story.
Obviously, Harry Potter himself is the central character. Then there are often the Dursleys, who would have to deal with Harry's early magic in different ways. Sometimes, Hagrid might also be involved earlier, coming to rescue Harry from the chaos caused by his early magic manifestations.
Obviously, Harry Potter is the central character. Since it's about him being blessed by magic. Then there's Hermione Granger and Ron Weasley, as they are his closest friends in the wizarding world and are likely to be involved in any story about Harry. Dumbledore is also often included as he plays a crucial role in guiding Harry in the original series, and his wisdom would be relevant if Harry has a new magical situation.
It's possible that the main character is the 'dark child' of course. There could also be a mentor - like figure, maybe an older wizard who tries to guide the child towards the light. And it wouldn't be surprising if there were some antagonists as well, such as other dark wizards who want to use the child's power for their own evil purposes.
It's difficult to determine exactly, but if the fanfiction focuses on the concept of the 'child of the green' being a new addition to the wizarding world, then that character would be central. There could also be other important characters like Draco Malfoy. Since Draco is from Slytherin, his path might cross with the 'child of the green' in interesting ways. And of course, we can't rule out the possibility of some magical creatures being significant characters in this fanfiction as well, like a magical snake or a forest - dwelling creature, considering the 'green' theme.
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.