Hermione could be a main character. She might help Harry understand the implications of being heir to multiple houses. Ron could also be important as he stands by Harry through all the new revelations. There could also be characters like Draco Malfoy. If Harry is heir to Slytherin, Draco's attitude towards Harry might change significantly, adding an interesting dynamic to their relationship.
Aside from Harry, Neville could play a significant role. Maybe he has some knowledge or connection related to the houses Harry is heir to. Luna Lovegood could also be a main character. Her unique perspective might help Harry make sense of the strange and often complex situations that come with being heir to many houses. And of course, the teachers at Hogwarts like Dumbledore and Snape could be involved, guiding Harry in different ways.
Maybe a jealous student or a group of students who feel threatened by Harry's new - found status. They could be from pure - blood families who think Harry doesn't deserve to be the heir of so many houses. They might start spreading rumors and causing trouble for Harry at Hogwarts, and eventually, their actions could lead to more dangerous situations as they side with darker forces out of envy.
In some cases, there might be new original characters created specifically for the fanfiction. These could be characters who have a connection to the ancient magic of Merlin and Morgana. For example, a mysterious wizard who has been guarding an artifact related to their power. They could initially be an enigma to Harry and his friends, but as the story progresses, they become an important part of the plot, either as an ally or an adversary.
The main character is usually the heir themselves. They could be an original character created for the fanfiction or a well - known character from the original series given a new twist. There are also often mentors from each of the houses the heir is related to. For example, a wise old Ravenclaw professor or a brave Gryffindor knight - like figure.
The dragon, of course, is a major character. It could be named something unique like 'Fyrstorm'. There might also be Hermione and Ron. Hermione would probably be worried about the legality and danger of raising a dragon, while Ron might be both scared and a bit excited about it.
Hermione would surely be involved. She could be Harry's research partner, helping him find relevant medical information in books and scrolls. Her intelligence and thirst for knowledge would be very useful in exploring new areas of medical magic. Another character could be Madam Pomfrey. She could be Harry's mentor, teaching him the basics of wizarding medicine and guiding him in his new role as a medic.
Since I haven't read this specific fanfic, it's hard to say for sure. But likely, Harry Potter would be one of the main characters as it's in the title. There might also be his friends like Hermione and Ron, as they are often part of Harry - centric fanfictions. And there could be new characters introduced that are related to the idea of him being the heir of many things, such as those who guard or know about the inheritances.
Well, it could be about Harry discovering he has some sort of ancient blood connection to multiple houses. Maybe he finds out that his family tree has been misread all along. For example, he could be related to the founders of Hufflepuff and Ravenclaw in some way. This could lead to him having special powers or abilities related to those houses, like being able to access their long - forgotten knowledge or having an affinity for Hufflepuff's loyalty - based magic.
Hermione could be a main character. She would probably be very involved in helping Harry with the baby, using her vast knowledge of magic to ensure the baby's well - being.
The supreme Mugwump himself could be a main character. He might have his own backstory, motives, and goals that drive the story forward.
One possible main character could be a Martian elder who takes Harry Potter under their wing and helps raise him. This Martian elder could have special knowledge about the planet and its hidden magic that they pass on to Harry.