Aspiring young writers who are fans of the magical world. They see Dumbledore as a rich character to base their fanfiction on. They could be students who are inspired by the detailed world of Hogwarts and want to contribute their own ideas about Dumbledore through writing.
Even some professional writers who are also Potterheads might write it. They could use their writing skills to create a more complex and in - depth story about Dumbledore, perhaps adding their own unique interpretations of his character based on their understanding of the original series and their own creativity.
There's also a chance that Dumbledore gets caught by a group of rogue magical creatures. For instance, if he was exploring an area that was supposed to be off - limits to wizards and the creatures there saw him as an intruder. They might not be as rational as wizards and could hold him captive without really understanding who he is.
The Ministry of Magic could be responsible. They might be jealous of Dumbledore's power and popularity. They could see him as a threat to their own authority and come up with some false charges to arrest him. For example, they could claim he was hiding information about a dangerous dark wizard.
Even some of the Hogwarts professors or students could catch Dumbledore. Maybe a curious student stumbles upon Dumbledore in a restricted area where he's doing something strange. Or a professor who has a different view on how to run the school catches Dumbledore in the middle of an action that they think is wrong for the school's environment.
Creatures that have been wronged by Dumbledore's decisions in the past could side with Rumple. For instance, if Dumbledore once restricted the rights of house - elves, the house - elves might assist Rumple in his revenge plan, believing that Dumbledore needs to be taught a lesson.
It could be Harry Potter himself. After realizing how he had been used, Harry might decide to hold Dumbledore accountable. Harry has the power and the motivation, having been through so much due to Dumbledore's actions or inactions.
Hermione would be a likely supporter. She is always loyal to Harry and if he presented her with evidence of Dumbledore's wrongdoings, she would probably side with him. She has the intelligence to help Harry strategize and find ways to expose Dumbledore. For example, she could use her research skills to dig deeper into Dumbledore's past.
The fanfiction could focus on Dumbledore's backstory. Fans might write about his early years at Hogwarts as a student, his friendships, and how he developed into the great wizard he became. It could also include his interactions with other magical creatures in more depth than the original series, such as having secret meetings with centaurs or merpeople to gain wisdom.
It could be Voldemort or his followers. They might see Dumbledore as a major obstacle in their path to power. So they could manipulate Harry, perhaps through some mind - control magic or by spreading false rumors, to get Dumbledore fired. By removing Dumbledore, they hope to gain more control over Hogwarts and the wizarding world in general.
Fans of Sonic who have a creative streak and an interest in exploring different scenarios for the character might write it. They could be young writers who are really into the Sonic universe and want to put their own spin on things.
Fred and George Weasley are very likely candidates. They are known for their love of pranks and their mischievous nature. They might see pranking Dumbledore as the ultimate challenge.