Well, Hisoka's origin story in Hunter x Hunter is quite interesting. He hails from Meteor City, a place that's more like a dumping ground for the unwanted. Growing up there, he was exposed to all sorts of things that normal people wouldn't experience. His love for fighting strong opponents probably stems from the fact that in Meteor City, strength was the only way to get what you want. Hisoka's nen abilities are also a product of his environment. He's constantly evolving and seeking new challenges, which is likely a trait he developed while growing up in a place where only the fittest survive.
One key element is his abnormal personality. He was born with a strange sense of what gives him pleasure, mainly fighting strong foes. Another is his lack of regard for normal social norms. He doesn't follow the usual rules, which allowed him to fully pursue his combat - related interests.
Hisoka's origin story is quite dark. He has always had a twisted sense of pleasure, especially when it comes to fighting strong opponents. He was born with a rather abnormal personality. From a young age, he showed little regard for the normal rules and ethics of society. His interest in battles and the pursuit of strong adversaries gradually shaped him into the character we see in Hunter x Hunter.
There's a fanfic called 'Hisoka's Obsession with Machi'. It delves into Hisoka's perspective. He is constantly intrigued by Machi's skills and her cold exterior. The story has some interesting scenes where Hisoka tries to get closer to Machi, and Machi is both repelled and fascinated by him at the same time. It's a really engaging read.
One great fanfic is 'The Unlikely Bond'. It delves into the complex relationship between Hisoka and Gon. The author beautifully captures Hisoka's twisted fascination with Gon and Gon's naivete in dealing with it. It has some really interesting plot twists that keep you hooked.
I really like 'Hisoka's Obsession'. It shows Hisoka's fixation on Gon in a more detailed and somewhat darker way. It adds layers to Hisoka's character while also developing Gon's reactions to Hisoka's strange behavior. The writing style is engaging and it's easy to get lost in this alternative take on their relationship.
Hisoka's upbringing in Meteor City made him very self - centered. In a place with no laws, he had to look out for himself first. So, he became someone who is only interested in his own desires, like his desire to fight strong opponents.
One popular Hisoka fanfiction might be those that explore his backstory. Since in the original 'Hunter x Hunter' his past is quite mysterious, fanfictions often fill in the gaps. For example, there could be stories about his early days as a Hunter and how he developed his unique nen abilities.
One common theme is the exploration of their opposing personalities. Hisoka is wild and unpredictable, while Machi is more reserved and practical. Fanfictions often play with how these differences can create either conflict or an unlikely attraction.