Another possible main opponent could be a power - hungry wizard within the Ministry of Magic. This wizard might be trying to implement unjust laws or gain more power at the expense of others. Hermione, with her strong sense of justice, would engage in a battle of wills to stop this wizard, using her knowledge, influence, and unwavering will to fight for what is right.
One idea could be Hermione facing off against a powerful dark wizard in a battle of wits. She uses her vast knowledge of magic and her strong will to outmaneuver the enemy. Another could be a battle of wills between Hermione and a group of pure - blood supremacists in Hogwarts who are trying to undermine her Muggle - born status. She stands her ground and uses her intelligence to expose their bigotry.
Madara Uchiha, if he were to somehow be involved in the Battle City scenario. His power level is extremely high, and his experience in combat is far greater than Naruto's at the start. Naruto would have to really dig deep and use all his skills, plus any new ones he's developed, to stand a chance against Madara in Battle City.
It could be that an external force, like a dark wizard in disguise, is the main antagonist. This dark wizard targets Hermione because of her potential to be a great threat to their evil plans. They use magic to cloud the minds of her friends, making them believe Hermione is up to no good. The friends, being under this spell, betray Hermione without realizing they are being manipulated. The dark wizard then watches as Hermione struggles with this betrayal, all part of their grand scheme.
Harry and Ron could be her main allies. They've always been by her side in the original story, so it's likely they'd support her new adventure as a dragon rider. They could help her keep her dragon - riding activities a secret from the teachers at Hogwarts.
Perhaps her main adversaries are a secret society within the wizarding world that has been operating in the shadows for centuries. This society might be made up of powerful and influential wizards who believe in a different order, one that involves subjugating non - pure - blood wizards. Hermione, with her Muggle - born status, is a prime target for them. They would try to undermine her at every turn, using their vast resources and political influence within the wizarding community. Hermione would have to fight not only their magic but also their attempts to smear her reputation.
Shadow could be a very challenging opponent. He has similar speed and abilities as Sonic, and in a death battle scenario, his more brooding and sometimes ruthless nature could give him an edge. Plus, if the Sonic watch is involved, Shadow might be more willing to use underhanded tactics to get it for himself or to stop Sonic from using it.
Bob Wills was likely a very important figure. Maybe he was a musician or an artist of some sort. Since he's called the 'king' in the story, he must have been highly respected in his community or field.
Another good opponent could be a character like Naruto from Naruto. Their powers are very different. Naruto has his ninjutsu and chakra, while Steven has his gem abilities. The clash of their ideals and fighting styles would make for a great fanfiction Death Battle.
McGonagall could be her coach. McGonagall is strict and has high standards, which would push Hermione to be the best she could be in gymnastics. She could use her Transfiguration skills to create unique training equipment for Hermione.
I recommend "A Beautiful Marriage: The First Daughter Is Respected" to you. The female lead of this novel is Xiao Mingyu. She is an elite in the modern workplace. She was reborn in a day and became a small first daughter of an ancient aristocratic family. She has also evolved into the female lead of the novel "The Alluring Shu Daughter." There was also a transmigrated female character. I hope you like this fairy's recommendation. Muah ~😗