the classic demon is a demon with a combat level between 500-600, they are so power because they have been locked away from many years after the new dragons had taken over, these demons can be located in the Mysterious Dungeon under falador and you need to use 1 of three amulets to get into there: The Classical amulet.these are very good to fight because of there drops such as classic bandos, dragon, rune, armadyl and they drop an extremely rare one which is the dragonfire shield and the disk of returning.