Well, the term 'h mate' is quite ambiguous. It could be a nickname for someone. If the story is about a group of friends, perhaps 'h mate' is the pet name that one friend uses for another whose name starts with 'h'. Or it could be a code name in a mystery - type story. If there are certain secrets or hidden agendas in the story, the 'h mate' could be the person involved in those. Maybe they are the mastermind behind some plot twists, or they could be the one who has some special knowledge that drives the story forward.
The 'h mate' could be significant in many ways. They might be the one who provides emotional support to the main character. In a story where the main character is going through a tough time, the 'h mate' could be the one who offers words of encouragement or a shoulder to cry on. Also, they could be the link between different parts of the story. For instance, if the story has multiple storylines, the 'h mate' could be the common element that ties them all together. They could also introduce new ideas or perspectives that change the course of the story. If they have a unique way of looking at things, their influence on other characters could lead to new developments and revelations in the story.
I don't think you should hate it. Maybe you just haven't found what you like about it yet. Maybe give it another chance and look deeper into the story and characters.
Hard to say. You'd have to look closely at the story and the interactions between the characters to determine if that's the case. Maybe there are clues or indications throughout the manga that would clarify it.