The OC could be a Muggle - born witch who had to hide during the war. Now, in the post - war period, she is eager to prove herself in the wizarding world. Ginny could be another character in the story, being Harry's friend and potentially having some influence on his relationship with the OC, either positive or negative.
Maybe the OC is a wizard from a different magical culture. For example, he could be from a far - flung wizarding community that was not directly involved in the war but has unique magical abilities. Neville could also be an important character, perhaps collaborating with Harry and the OC on projects to revive the magical plants that were damaged during the war.
A potential character could be a reclusive old wizard who lives on the outskirts of the wizarding world. This wizard might have his own reasons for living in seclusion, but when he sees Harry's loneliness, he takes him under his wing. Another character could be a young, orphaned witch who is also trying to find her place in the post - war wizarding world and she crosses paths with Harry.
One potential Quidditch superstar in fanfiction could be a new transfer student. This student could have been a star player in their previous school's Quidditch team and brings a whole new set of skills and strategies to Hogwarts. Maybe they have a unique flying style that no one at Hogwarts has seen before.
Hermione would most likely be one of the main characters. She's always observant and caring towards Harry. So when she notices something is off with Harry, she would do everything in her power to figure out what's wrong and help him. She might use her extensive knowledge of magic to find a solution to his emotional distress.
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.
Hermione would surely be there. She might be a fellow professor, teaching a subject like Transfiguration or Ancient Runes. She could be Harry's confidante and help him with academic matters at Hogwarts. Also, Ron could make an appearance, perhaps as a visiting lecturer from time to time, sharing his knowledge of wizarding chess and other aspects of wizard culture.
His child, of course. Depending on the story, the child could be a young boy or girl. If it's a boy, he might be eager to learn magic from his father and get into all sorts of mischief at Hogwarts when he's old enough. If it's a girl, she could be more interested in the magical creatures and want to follow in Hagrid's footsteps.
Hermione could be involved. She might follow Harry through time to try and stop him from becoming the Dark Lord or to fix the timeline if he already has. Dumbledore is another character. In the past, he could sense something strange about Harry's presence and try to guide him away from the dark path. Young Tom Riddle would definitely be involved. He could be either an ally or an adversary to Harry, depending on the plot. Maybe he sees Harry as a kindred spirit or as a threat to his own rise to power.
I think Dobby could be an important character. Since Harry is raising himself, Dobby might take it upon himself to secretly help Harry. He could provide some food and small comforts when Harry is all alone. Another character could be Hedwig. She would be more than just a pet; she could be Harry's only true companion, helping him in small ways like delivering messages or even warning him of danger.
The main characters could include the butterfly's kin. For instance, if the butterfly is part of a colony or a family of magical butterflies, they would all be important. They might have different abilities and personalities. There could also be a wise old owl in the butterfly's world that acts as a guide for Harry, teaching him about the new world he's in. And don't forget about the possible presence of a shadowy figure that lurks in the background, representing the unknown danger that Harry has to face.
Well, first off, Ursula is an obvious main character as she is related to Harry in this fanfiction. Then there's Hagrid. He has always been there for Harry and would likely play a role in helping Harry deal with this new situation. Neville could also be an important character. He might be one of the few who initially believes in Harry and doesn't immediately turn his back on him because of his new identity. And then there are the Weasley family members. They might be a bit hesitant at first but would eventually come around to help Harry as they have always been a big part of his life at Hogwarts.