Mercedes Lackey said this quote

It seems to me that evil is a kind of ultimate greed, a greed that is so all-encompassing that it can't ever see anything lovely, rare, or precious without wanting to possess it. A greed so total that if it can't possess these things, it will destroy them rather than chance that someone else might have them. And a greed so intense that even having these things never causes it to lessen one iota -- the lovely, the rare and the precious never affect it except to make it want them.