One popular theme is adventure. Since Gon and Killua are often on adventures in the original story, fanfictions may continue this trend while adding the element of Hisoka's interference. Another theme is the exploration of power dynamics. Hisoka is much more powerful than Gon and Killua at first, so how they grow to face him or interact with him in terms of power is interesting.
The relationships in 'hisoka x gon x killua fanfiction' can vary greatly. Some fanfictions might focus on a possible rivalry between Hisoka and Killua over Gon. Hisoka may see Killua as an obstacle to his 'play' with Gon. Meanwhile, Gon might be oblivious to the full extent of Hisoka's intentions. This creates a dynamic triangle where different emotions like jealousy, friendship, and obsession play out, making for a very engaging read.
One great Gon x Killua x Hisoka fanfiction is 'Unlikely Alliances'. It explores their complex relationships in a unique adventure setting. The story does a wonderful job of showing how Gon's pure heart, Killua's loyalty, and Hisoka's unpredictability interact in different situations.
One common theme is the exploration of power dynamics. Hisoka is much more powerful than Gon and Killua at first, so fanfics often play with how they either try to overcome this gap or how Hisoka uses his power in relation to them.
Gon in fanfiction can be very single - minded in his pursuit of goals, just like in the original. He might be a bit more naive at times, which can lead to interesting plot twists. Killua is often portrayed as having a complex emotional side. He struggles with his past as an assassin and his loyalty to Gon. His cool exterior may crack in some fanfictions, showing his true feelings.
Gon would probably be angry at first. He has a strong sense of justice and being kidnapped against his will would surely make him mad. He'd try to fight back immediately if he had the chance.
Often, they show a deeper level of commitment. The mpreg forces them to rely on each other more. For example, Gon might become more protective of Killua during the pregnancy.
In some fanfictions, Gon might initially be shocked. He has seen Hisoka as a somewhat eccentric but strong ally. When he discovers Hisoka's more sinister side, like his love for fighting to the death and his disregard for normal moral boundaries in battle, Gon could be conflicted. He might feel a sense of betrayal because he thought Hisoka was more on the side of 'good' in their adventures. However, Gon's own sense of justice and his unwavering belief in his friends could lead him to confront Hisoka about his true nature.
In 'killua x gon fanfiction', one characteristic is the exploration of their relationship in different scenarios. It could be in alternate universes where they face new challenges. Also, their friendship is often romanticized to some extent, with the authors delving into the unspoken feelings they might have for each other. Moreover, the fictions usually stay true to their personalities as shown in the original anime, while adding new layers to them.