If the beginning is changed, like if the Philosopher's Stone was never hidden at Hogwarts, then the whole first year's plot would be different. There would be no need for Harry, Ron, and Hermione to go on that adventure to stop Voldemort from getting it. This would mean different relationships would form as they wouldn't have had that shared experience.
If a fanfiction features a super - powerful wand, it can completely change the power balance in the story. For example, if the protagonist gets a wand that can break any protective spell easily, they can access places that were previously inaccessible. This can lead to a different kind of adventure, like exploring ancient, forbidden magical tombs.
It could be a rewrite where Harry is raised by someone other than the Dursleys. For example, if he was raised by Sirius Black from the start, his whole outlook on magic and the wizarding world might be different. Sirius would have taught him about his family's noble history and perhaps some dark magic secrets earlier, which could change how Harry approaches challenges at Hogwarts.
It can greatly change the plot. If Harry has a different name, like Ethan, for example, Voldemort might not target him as easily. This could delay the start of the main conflict in the story. Or, it could cause the Order of Phoenix to be more cautious in approaching him as they may not be sure if he's the 'Chosen One' with this new identity.
The 'darkness' can make the plot more complex. It might introduce new challenges for the characters that they have to overcome. For example, if there are new dark spells or dark creatures in the fanfiction, the characters need to find ways to deal with them.
It can create immediate conflict. If a young wizard performs magic accidentally, the Trace can bring the Ministry's attention, like in some fanfics where a minor character's small magic act sets off a chain of events because the Ministry gets involved.
Rituals can also be a way to explore different magical cultures in fanfiction. For example, if a ritual from an ancient wizarding tribe is introduced, it can bring in new lore and magic. This can expand the world - building of the Harry Potter universe in the fanfiction. If the main character has to learn and perform this ritual to save the day, it not only affects the immediate plot but also enriches the overall story by adding depth to the magical world and its history. It can also lead to the discovery of long - lost magical artifacts or secrets that were tied to that ritual, which can further drive the plot forward.
The different wand can change Harry's magical abilities, which directly impacts the plot. If it's a more powerful wand, he might be able to defeat enemies more easily, or if it's weaker in some aspects, he could face more challenges. For example, in a fight against Voldemort, a different wand might give him an unexpected advantage or disadvantage.
Well, without actually reading it, it could be about a new start for the Harry Potter characters. Maybe it's a rewrite of the original story from a different perspective, like starting from a point where a minor character gets more focus and changes the course of events.
For Harry, a different potions class might make him more interested in the subject. Since he often had a tough time with Snape, a new teacher or teaching style could make him see potions in a new light. He might start to enjoy the process of making potions and even excel at it. Hermione, on the other hand, would probably adapt quickly to any changes. She might use the new opportunities in the class, like new potions to study, to expand her knowledge even further.
The protective brother can change the plot significantly. For instance, if he's highly skilled in magic, he can prevent Harry from getting into some of the dangerous situations he faces in the original series. He might be able to stop Harry from entering the Triwizard Tournament by interfering with the Goblet of Fire's magic. This would then change the entire course of that year at Hogwarts and Harry's relationship with Cedric Diggory and others.