Well, in the 'Harry Potter adopted by the Flamel's fanfiction', it's possible that Harry's understanding of magic would be completely transformed. Since the Flamels are known for their long life and great magical achievements. Harry could be introduced to a whole new world of alchemy. He might even get involved in some quests related to the Philosopher's Stone that the Flamels created. This would change his role in the wizarding world significantly as he would no longer be just the Boy Who Lived, but also a protege of the Flamels with unique magical abilities and knowledge.
In this kind of fanfiction, Harry Potter might gain access to the Flamels' vast knowledge of magic. Maybe he would learn ancient spells and potions that are not taught at Hogwarts. He could also be protected by the Flamels' powerful magic, making him safer from Voldemort and his Death Eaters.
Perhaps Nicholas Flamel, being extremely old and wise, trains Harry in a very different way than Dumbledore or the Hogwarts professors. He might focus on teaching Harry about the balance of magic and nature through alchemy, which gives Harry a new perspective on magic and how to use it against the Dark Arts.
Well, in such a fanfiction, perhaps the train could be a key to finding Flamel's hidden secrets. Maybe it has some sort of magic protection put in place by Flamel himself. It could be that the train is transporting something very important related to Flamel, like a special ingredient for his alchemy.
Obviously, Harry Potter is one of the most important characters. Then there are the Flamels. Nicolas and Perenelle Flamel are central as they are the ones adopting Harry. Dumbledore might still play an important role as he has a connection to Harry and also to the Flamels in the wizarding world. Voldemort would also be important as he is Harry's main enemy, and the change in Harry's situation due to the adoption could affect their ongoing battle.
In such a fanfiction, Harry might gain access to Flamel's vast knowledge of alchemy. Maybe he would learn how to create powerful potions and magical items much earlier. Flamel could also protect Harry from Voldemort more effectively with his ancient magic and connections.
In this fanfiction scenario, Harry could bring a touch of magic to the royal court. He might introduce some magical creatures to the royal gardens, like a friendly unicorn or some magical birds. His Gryffindor courage would make him stand out in royal events, and he could inspire the younger members of the royal family to be more brave and adventurous. Also, his experience with fighting dark wizards could be applied to protecting the Queen from any potential threats, magical or not.
His character would likely become more studious and curious about ancient magic. Since Flamel is associated with alchemy, Harry would be exposed to a different type of magic, which would make him more eager to learn.
He would likely become more knowledgeable in alchemy. Harry's always been eager to learn, and with Flamel as his mentor, he'd soak up all that alchemical wisdom. This would make him more confident in his magical abilities.
It could be in a magical alternate universe. Maybe a place where the rules of magic are different and allow for such a transformation.
In such a fanfiction scenario, Harry would likely grow up in a very different and dark environment. Bellatrix is a Death Eater, so Harry might be indoctrinated into the Dark Arts from a young age. His view of the wizarding world would be skewed towards Voldemort's ideology. He may also develop a more ruthless and aggressive personality, different from the kind - hearted Harry we know in the original series.
In such a fanfiction, Harry's life would take a very different turn. Since Lucifer is a powerful and often mischievous or evil figure in many stories. He could introduce Harry to a world full of demons and other supernatural beings. Harry would have to struggle with his own identity and values. For example, he might be tempted to use Lucifer's power to get revenge on those who wronged him at Hogwarts, like the Dursleys or Draco Malfoy. But he also has the good nature that he got from his parents and friends at Hogwarts. It would be a constant battle between the good in him and the dark influence of Lucifer.