In this fanfiction, it's possible that some of the older and more experienced wizards who have retired from active duty could become Harry's allies. They might see the potential in Harry and decide to share their knowledge of battle magic with him. Also, there could be some magical creatures, like the centaurs, who, if Harry manages to gain their respect, could offer their unique skills and knowledge as allies in his battle magic journey.
Dumbledore's Army members could be allies. They've been through a lot together. Neville, for example, has shown great courage. He could join Harry in learning and using battle magic. And there might be some new characters introduced specifically for this fanfiction who have their own special battle magic skills and become Harry's allies in his fight.
Hermione could be a strong ally. She's smart and could help Harry research more about battle magic. Ron too, with his loyalty and courage, would be by Harry's side.
He could lose his friends. In the original story, his friends stand for good and oppose black magic. If Harry starts learning it, they might turn their backs on him. Also, he could be ostracized by the wizarding community. The wizarding world has a clear stance against black magic, and Harry would become an outcast.
In some fanfictions, Harry might learn family magic that has to do with time manipulation. His family could have had a special talent for seeing into the past or future. As he delves into this magic, he has to learn to control it carefully, as misusing time - related magic can have serious consequences. He may use this new - found magic to prevent certain disasters or to gain knowledge from the past that could change the course of the wizarding world.
One of the interesting spells could be 'Tempestus Ignis' which creates a fiery storm in some fanfictions. It gives him a powerful offensive move against dark creatures.
Well, perhaps we can expect to see Harry develop new and powerful combat spells. He might face some really tough opponents and use his newly learned battle magic to overcome them.
His friends like Ron and Hermione would surely be his allies. They have always been by his side in the original stories, so it's likely they'll be there in the fanfiction too, helping Harry in his fight.
Obviously, Harry Potter is the main character as the title implies he is the one learning magic early. But there could also be Hermione and Ron. Hermione might be intrigued by Harry's newfound knowledge and Ron could be both a bit jealous and in awe of Harry's early magical abilities.
Obviously, Harry Potter himself is a very important character as the story revolves around him learning family magic. His friends like Hermione and Ron might also be important as they could support or help him in his journey of learning this magic.
Well, he might use soul magic to communicate with the spirits of the dead wizards. It could give him an edge in battles as he might understand the essence of his opponents' souls.
It could be an older relative who was thought to be dead but actually has been living in seclusion, waiting for the right time to teach Harry about their family magic. This relative might have a vast knowledge of the family's magical traditions and spells.
Perhaps it's a magical crystal that enhances his ability to communicate with magical creatures. This would be quite unique as it would give him an edge in dealing with things like thestrals or unicorns, and open up new storylines in the fanfiction. Harry could use this crystal to understand their needs and gain their help in various situations.