It could be a rogue hunter who has his own twisted ideas about the use of Nen. This hunter might see Pokkle and Ponzu as obstacles in his quest for power and knowledge. He could try to capture them to steal their Nen abilities or the information they have about certain areas of the Hunter x Hunter world.
One idea could be that Pokkle and Ponzu discover a hidden area in the Hunter x Hunter world filled with unique and powerful creatures. They have to team up with some unlikely allies to survive and document these new finds.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.
The Hunter x Hunter manga has indeed concluded. However, the ending might have left some fans wanting more or with mixed feelings depending on their expectations.