Maybe a long - lost relative of Voldemort. This character could inherit some of his dark powers and have a natural inclination towards the dark arts. They could emerge as a new and dangerous dark arts master, causing chaos in the wizarding world and challenging Harry and his friends in ways not seen before.
A former Hogwarts student who was bullied and ostracized could turn to the dark arts. They might feel that the traditional wizarding society has failed them, so they decide to embrace the dark arts to gain power and respect. This character could be a complex and interesting dark arts master in fanfiction, as they would have a backstory that readers could sympathize with to some extent, while also being horrified by their actions.
Bellatrix Lestrange could be a potential focus as a dark arts master in fanfiction. She already has a deep knowledge of the dark arts in the original series. Fanfiction could explore her even more, perhaps showing her training others in the dark arts in a more in - depth way.
There could be a dark arts teacher who is actually a double - agent. This character might seem to be teaching Harry the wrong things at first but is actually guiding him to use the Dark Arts for good. Another new character could be a mysterious figure from an ancient dark arts cult who tries to recruit Harry for their own purposes.
Well, perhaps in this fanfiction, Harry Potter might start exploring the Dark Arts not in an evil way but to understand his enemies better. He could learn some of the forgotten or forbidden spells to use them against Voldemort's more dangerous followers.
Well, some fanfictions might have a plot where the dark arts master has a unique connection to an ancient and powerful dark magic artifact. This connection could drive the story as the character tries to either master the artifact's power or keep it from falling into the wrong hands, all while dealing with the challenges in the Harry Potter universe like avoiding the Ministry of Magic's detection.
One potential consequence could be a change in his relationships. His friends might be worried or even turn against him. For example, Hermione, who is always concerned about following the rules and doing what's right, would likely be very troubled. Another consequence could be a shift in his own moral compass. The dark arts are often associated with negative and unethical actions, so he could start to make more morally ambiguous decisions.
A less obvious candidate could be a corrupted Dumbledore. Imagine if he was swayed by the allure of absolute power and became the dark king. It would be a huge twist as he is seen as a symbol of good in the original books.
There could be some disillusioned wizards who have lost faith in the current state of the wizarding world. They might see the Dark Prince as a way to change things, even if his methods are dark. These wizards could be those who have been marginalized or have suffered losses during the war. They believe that the Dark Prince has a vision for a different kind of wizarding society, not realizing the full extent of his dark intentions.
In this fanfiction, the Dark Prince might find allies among those who have been wronged by the Ministry of Magic. If there are wizards who have been unjustly punished or whose families have been persecuted, they could be swayed to join the Dark Prince. There could also be some international dark wizards who see an opportunity to expand their influence in the British wizarding world through an alliance with the Dark Prince. Another possibility is that there are some dark entities from other dimensions or realms that the Dark Prince manages to summon and convince to be his allies.
The Dark Arts in Harry Potter fanfiction are fascinating as they can change the whole dynamic of the story. They can create new villains or give old characters a darker side. Fanfiction authors might use the Dark Arts to create alternate storylines where Hogwarts is in more danger than ever. It gives a chance to see how different characters would react to a more prominent and menacing presence of Dark Magic.
It could be an original character created specifically for this fanfiction. Maybe a young wizard or witch who has always been an outcast in the wizarding world and discovers their unique ability to connect with dark dragons.
Another possibility is a reformed dark wizard. Someone who has seen the error of their ways and now uses their in - depth knowledge of dark magic to teach students how to defend against it. This character would have a very interesting backstory, having once been on the wrong side but now using their experiences to help the next generation of wizards in the DADA class.