Dark beasts are level 182 monsters that can be found on Lunar Isle and in the Slayer Dungeon. They are often killed as a Slayer task monster, but can also be killed for their rare drops. It's recommend to use the 'Protect from Melee' or 'Deflect Melee' prayer activated, because dark beasts can hit very high when you do not have protection prayers on. Dark beasts require a slayer level of 90 to kill.