A plot could involve Hisoka using his nen abilities in the wizarding world. He could be mistaken for a dark wizard at first. But then, as the story progresses, he teams up with Harry Potter and his friends. Hisoka might teach them some of his unique combat skills in exchange for learning more about magic. For example, he could show them how to use their instincts better in a fight, which could be useful against Voldemort and his Death Eaters.
There could be a new character created specifically for the fanfic. A dark wizard who has been observing the wizarding world from the shadows and sees Hisoka's arrival as an opportunity. This new antagonist could try to use Hisoka to achieve his own evil goals, like opening a portal to a dark dimension or stealing all the magic in the world. When Hisoka realizes he's being used, he would turn against this new antagonist, and Harry Potter and his friends would join him in the fight.
A Toshiro x Hisoka fanfic often explores the unique dynamic between these two characters. It might delve into their contrasting personalities. Toshiro is typically calm and composed, while Hisoka is more unpredictable and flamboyant. The fanfic could be about how they interact in different scenarios, like a battle or a mission together, where their different approaches to things create interesting storylines.
There are some out there. However, since Harry Potter and Hisoka are from different fictional universes, such fanfictions can be quite creative and often involve bending the rules of both worlds to make the relationship work. Some might focus on how their magical abilities could interact in unique ways.
One common theme is the exploration of an unusual relationship. Given Hisoka's eccentric nature and Gon's pure - heartedness, their relationship can be very complex in fanfics, often blurring the lines between friendship, rivalry, and something more.
One common theme is danger. Hisoka is a very dangerous character, and in these fanfics, the reader often finds themselves in precarious situations because of him. For example, they might be caught up in his battles or his schemes.
Many 'gon x hisoka fanfic' also have the theme of redemption. Hisoka is a rather morally ambiguous character. Fanfics may explore if and how he can be redeemed through his relationship with Gon. It adds depth to the story and makes for a more complex and thought - provoking read.
Another theme is power. Given that both are very powerful in their own ways, fanfics often deal with how they compare their powers, use their powers in relation to each other, or how their powers influence their relationship.
There's 'A Different Path' which is a 'gon x hisoka fanfic' that shows Hisoka being protective of Gon in a very unique way. It has some really interesting plot twists that keep you hooked. The author does a great job of writing their relationship in a way that's both believable and exciting.