The great debate on the wisdom of having items that are just too powerful for player's control will not be resolved anytime soon. Suffice it to say I feel my item is in that catagory as it is a blatantly evil item that is completely self serving. Even if your characters are of an evil bent, the device will always attempt to subsume the user for its own purposes (like the One Ring).
I chose to have the Devourer be a reflection of Hunger. I leave it up to your imagination to determine what would happen if these two items were ever brought together (would Darnakurian rise from his stasis and continue his swath of destruction? would the icy cold of Bitterness and Icespire start to spread?). I made no suggestions on how to destroy these items, for now all that is know is that they must be kept hidden and unused. Whole adventures can revolve around researching a method to destroy Hunger and Devourer and thus ending the threat from these vile items forever.