These mobs are immune to most (but not all) magic effects in the game, including wands. They are vulnerable to stuns, but not poisons. They resist hunter traps. The Mana Feeders do not follow any discernable aggro rules and change their targets at random. It is advisable for everyone to stand close together in a tight cluster to prevent the mobs from running all over, as well as make maximum use of Cleave, Whirlwind and Blade Flurry. If you have hunters in the group they can stand away from the main group. Do not have them chase the mobs to the hunters, they will return when they Feign Death.