User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-5172919-20141106014426/@comment-5933391-20141106202010

Only certain quests get harder (the guild quests in the Mysterious Forest). They level up as you do them more but it's different then their HR. They start at low or high rank level but eventually they get even harder then G rank. I believe that monsters also become extreme at one point or another.