Another possibility is that there could be an evil succubus queen. If Harry's succubus familiar has escaped from her, the queen might come after them. She would be a powerful antagonist, using her charm and magic to try and take back the familiar and harm Harry in the process.
The main antagonist could be the Ministry of Magic if they view the succubus as a dangerous and uncontrollable creature. They might try to separate Harry from his familiar, and in the process, become the main force that Harry has to oppose.
Well, perhaps the succubus could initially be a mystery to Harry. She might seem like an ordinary creature at first, but then he discovers her true nature. Maybe she helps him in some unexpected ways in his battles against Voldemort, like using her unique powers to distract the Death Eaters.
Maybe there's a demon lord who has some sort of claim over the succubus. This demon lord sees Harry's binding of the succubus as an insult and a threat, and thus becomes the main antagonist. He would then send his minions or use dark magic to try and break the bond between Harry and the succubus.
Perhaps a group of anti - dragon fanatics within the wizarding world could be the main antagonists. They see the dragon as a dangerous and uncontrollable creature and will do anything to get rid of it, even if it means going against Harry.
It could be a rogue wizard who is jealous of Harry's new cybernetic abilities. This wizard might think that Harry is polluting the purity of magic with technology and decides to stop him at all costs.
In this fanfiction, it might be that the main antagonist is actually a part of Harry himself. His inner demons, so to speak. The 'wasted' state could bring out his insecurities and negative traits, and these could manifest as an internal struggle. So, in a way, Harry is his own antagonist as he has to overcome this self - destructive side of him.
A succubus familiar can be incorporated by first establishing its magical nature. For example, it could have powers related to charm and allure, which are common traits of succubi. In a fanfiction, it might be a familiar that a dark wizard or an outcast wizard has. The succubus familiar could use its charm to help its master in various ways, like getting information from other characters or sneaking into restricted areas.
There could be. Fanfiction writers are very creative and they come up with all sorts of ideas. But it might be a bit of a niche concept. You could start by looking on large fanfiction platforms like Archive of Our Own or FanFiction.net. Search for 'Harry Potter' and'succubus familiar' and see if anything comes up. It's also possible that it exists but is not very well - known or popular yet.
In such a fanfiction, it could be a very strange and unique scenario. Harry might face a lot of internal conflict. Loving a succubus, which is often associated with dark and alluring yet dangerous entities in mythology, would put him at odds with his normal values. He might struggle to reconcile his feelings for this otherworldly familiar while also trying to maintain his place in the wizarding world.
Voldemort could still be the main antagonist. Even with a new wand, Harry is still a threat to him, and Voldemort would be eager to get his hands on such a unique and powerful wand.
Well, it could be really interesting. A succubus is often depicted as a seductive and otherworldly being. In this fanfiction, perhaps the succubus familiar would help Harry in ways that are different from his normal magical friends. It might use its unique powers to assist him in battles, like confusing the enemies with its charm. Or it could also bring some chaos to Hogwarts as its nature might not always align with the school's rules.