One way is through intense training. In fanfiction, a character might undergo extreme physical and mental training regimens that push their limits. For example, Gon could train in isolation with more powerful nen masters, learning new and advanced nen techniques that weren't shown in the original series. This could include more complex manipulation of his aura, like creating multiple types of nen beasts for different purposes.
One popular theme is the underdog rising to power. Many fanfictions focus on characters who were initially overlooked or weak in the original series, like Kurapika's side characters from his clan. They might start with very little power but through determination and some unique circumstances, they become extremely powerful. This gives readers a sense of satisfaction as they see the 'little guy' succeed.
It's hard to say for sure, but Naruto could be a very strong contender. His ability to create countless clones and his massive chakra reserves would give him an edge. Plus, his Sage Mode and later forms are extremely powerful. However, Ging from Hunter x Hunter also has a lot of mystery and power surrounding him. He might be able to outwit Naruto in a battle of wits. But then again, Sasuke with his Rinnegan and Sharingan abilities could also be very formidable in this crossover.
The 'hunter x hunter meruem x oc fanfiction' often explores unique relationships. It might show how an original character (OC) interacts with Meruem. Maybe the story focuses on the OC influencing Meruem's view of the world, or vice versa. It could also be about their adventures together in the complex world of 'Hunter x Hunter'.
There's a fanfic called 'Meruem's New Path'. In this story, Meruem survives his battle and tries to find a new purpose in the world of Hunters. It has a unique plot that keeps you hooked from start to finish. The writer does a great job of staying true to Meruem's complex personality.
I really like 'A Hunter in Beacon'. It starts with a Hunter x Hunter character somehow ending up in the RWBY universe at Beacon Academy. It has a lot of action scenes that are both exciting and true to the nature of both franchises. The author does a good job of making the interactions between the characters from different universes believable.
One great Neferpitou fanfiction is 'The Redemption of Neferpitou'. It shows an alternate storyline where Neferpitou tries to understand the concept of humanity more deeply. Another interesting one is 'Neferpitou's Journey'. It explores Neferpitou's growth and development in a world post - Chimera Ant arc. There's also 'Neferpitou and the Lost Soul' which delves into Neferpitou's encounter with a mysterious being that challenges its very nature.
There's also 'Hunter x Hunter meets Ranma 1/2: The Adventure'. This one takes a more light - hearted approach. It has some really funny moments as the characters from both series misunderstand each other's cultures. The fanfic does a great job of exploring the comical side of a crossover.
One great 'Hunter x Hunter Chrollo Fanfiction' is 'Chrollo's Redemption'. It explores an alternate path for Chrollo where he tries to atone for his past sins. The story has really good character development and the author does an amazing job of getting into Chrollo's psyche.
One great 'Naruto and Hunter x Hunter' fanfiction is 'The Cross - Over Quest'. It combines the unique worlds and power systems of both series in an interesting way. The main character, who has abilities from both Naruto and Hunter x Hunter universes, embarks on a journey to save both worlds from a common threat. It's full of action - packed scenes and well - written character interactions.