A brave knight could be a main character. He might be on a mission to prove his courage by getting close to the sleeping dragon without disturbing it. Or a young mage who is curious about the dragon's magic and wants to study it while it sleeps.
Maybe an elf with exceptional stealth skills. The elf could be scouting the area where the dragon sleeps and accidentally stumbles upon it. They then have to decide whether to leave it be or try to interact with it in some way without waking it. Another possibility is a dragon trainer in training. They've heard tales of this sleeping dragon and want to see if they can establish a connection with it even in its slumber.
One idea could be that a young and curious character accidentally gets too close to the sleeping dragon while exploring its lair, and has to figure out how to escape without waking it. Another could be that there's a magical spell that causes the dragon to have strange dreams, and the protagonist must enter the dragon's dream world to undo the spell.
Obviously, the sleeping dragon and the weak fairy would be the main characters. There could also be other characters like the fairy's friends or family who might be worried about her going near the dragon.
Since I don't know the details of this 'never ending dragon dragon story', I can't say for sure. But it's likely that the main characters would be dragons. There might be a heroic dragon, a wise old dragon, or a young and adventurous dragon.
It could be two siblings. They often go to the creek together. One is always teasing the other by tickling near the water, and the other tries to get revenge. So they are the main characters in this fun 'creek tickle fanfic'.
One possible main character could be a kind - hearted human boy. He's curious about the world of monster girls and is open - minded enough to form a bond with one. The monster girl could be a cat - like creature, with soft fur and big ears. She's playful and loves to be tickled, which makes for some fun interactions between them.
A young girl who has always been fascinated by dragons could be a main character. She might be an outcast in school until she discovers her ability to communicate with dragons.
The Dumbledore character could still be important. He might be secretly watching over Harry, guiding him from a distance. Another character could be a new wizard or witch that Harry meets in the Muggle world who has a special mission related to Harry. For example, a young witch who has been exiled from the wizarding world but has the knowledge to help Harry understand his powers. And of course, Voldemort would still be a main antagonist as his threat looms over the entire wizarding world whether Harry is at Hogwarts or not.
Perhaps a young wizard who teams up with the dragon. The wizard could use magic to assist the dragon in their adventures.
Obviously, Sakura is one of the main characters. As for the enemy, it could be a character who has been opposing Sakura's side in the original story. It might be someone with a dark past or different motives.
The main characters could include the leaders of the Freys. They would be the ones making the decisions on how to deal with the dragon attacks. And the dragon itself, which might have unique characteristics or abilities that make it a formidable foe. Additionally, there could be a wizard or sorcerer who either tries to control the dragon or help the Freys defend against it. They would play important roles in the story as they bring different elements of power and knowledge to the situation.