Well like a first boss mean the easy boss and harder boss after it like your pokemon game when you get every pokemon you go to another island
Sorry, I'm really not sure I understand what you mean here.
This is what i mean dragon girl is boss for island and after we beat her we can go to another island different and harder monsters
I get you now! This game's story doesn't really work like that I'm afraid, the Hunter is locked into one region and isn't allowed to leave