There are different kind of hunters, almodt one for every supernatural creature existing. The ones who hunt all kind of supernatural creatures are simply named "Hunters" while hunters specificed in one supernatural creature is named first the supernatural creature's name and then the word "hunter" after, like for example: "Vampire Hunter" or "Werewolf Hunter".
Hunters are ordinary humans. Some however has supernatural abilities or other magic powers. All hunters have the skill to track of how to track and useful, inside information and great knowledge helping them to track, the specific supernatural creature. The skill goes through generations even if it might not be visible before awakening their true calling.