The relationship could also be developed through a misunderstanding. At first, the hunter might think the witch is a threat to all survivors. But when he sees her sparing some survivors or leading zombies away from a group, he starts to question his assumptions. This could lead to him approaching her more carefully, and eventually they start to communicate in their own way, perhaps through gestures or simple sounds. As they communicate more, their relationship changes from one of enmity to something more ambiguous and potentially positive.
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.