User blog comment:Mckrongs/Monster Hunter Frontier Season Forward 3/@comment-5020152-20120416011342/@comment-969093-20120418200950

They're nothing like HardCore quests. HC Quests are accessible from HR500 onward. Aside from some requiring certain SRs to be joined, I don't know much else about them.

HC Quests can be for monsters of all 3 ranks (Low/Upper/Henshu & Gou). A player, as far as I know, can decide to turn a regular monster into its HC variant. HC Monsters are much faster, hit much harder, have totally new behavioural patterns and give unique carves that have ridiculously low drop rates.

Another general trait of HC monsters is buffed up wind pressure and screams. The majority will be generating Dragon Wind and SHGE roars.