Obviously, Harry Potter himself is the central character. Hermione and Ron are also likely to be important characters as they are Harry's closest friends and often accompany him in his adventures.
There could be some original characters created by the fanfiction authors. For instance, a new student at Hogwarts who has some special knowledge or ability that helps Harry in unlocking his power. Or an old wizard who was once a friend of Harry's parents and now comes back to aid Harry in his journey of power - unlocking.
Dumbledore might also play a significant role in these fanfictions. He is very wise and powerful, and could be the one who gives Harry some crucial hints or guidance on unlocking his power. And of course, Voldemort is often present as the main antagonist, which might be the driving force for Harry to unlock his power in order to defeat him.
In some fanfictions, Harry might unlock his power through a special ancient magic he discovers in a hidden chamber at Hogwarts. This magic could be related to the founders of the school.
Obviously, Harry Potter himself is a central character. His sister would be the new addition. Hermione and Ron are likely to be there as well. They are Harry's best friends in the original series and would probably play important roles in the fanfiction too. Dumbledore might also appear, as he is a very important figure in the wizarding world and could guide the sister in her magical journey.
Another common character could be Hagrid. He was such an important part of Harry's life at Hogwarts and might continue to be in the fanfiction, perhaps coming over to the Potter family's house to show the kids some new magical creatures or give them some advice on their magical studies. There could also be characters from the Ministry of Magic, like some new Aurors who interact with the Potter family in different ways, either as friends or as those who are a bit suspicious of their activities.
Ron could also be there. He might be initially scared of the dragon but then grows to like it. His loyalty to Harry would make him support Harry's decisions regarding the dragon, even if they seem risky. For example, when they need to hide the dragon from the Ministry of Magic, Ron would be right there with Harry, coming up with crazy but effective plans.
Obviously, Harry Potter is the main character as it's about him hiding his power. His friends, like Hermione Granger and Ron Weasley, are also likely to be main characters. They might be in the dark about his hidden power at first, which could create some interesting dynamics in their relationships.
Well, it's hard to say for sure without reading it, but likely Harry Potter would still be a central figure. He might be in a more mature and powerful role, perhaps having to face even greater threats to the wizarding world.
It's hard to say for sure without reading it, but it could be Harry Potter himself. He often finds himself in the middle of things and might be involved in establishing or dealing with the power of order. Hermione could also be a main character as she is intelligent and would likely play a role in any new system of order. Ron might be there too, providing his loyalty and courage.
In many fanfictions, there are often original characters created by the author. In 'harry potter and the power of beast fanfiction', there could be a young wizard or witch who has a hidden connection to the power of the beast. They might be the key to unlocking the secrets of the beast's power. But of course, Harry Potter and his friends would likely be involved in some capacity, perhaps as mentors or allies to this new character, depending on how the story is crafted.
I don't know for sure since I haven't read this particular fanfiction, but it could be Harry Potter himself, or perhaps a new character that the author has introduced to have these god - like powers.
Harry Potter himself is often a popular character in these fanfictions. But with an alt power, like being able to communicate with magical creatures on a deeper level than before. This changes his interactions and his role in the story.