Its all about the evolution of the human nature, yes we give tones and shades to nature, sunstone says nature is evilless and goodless and hes right, but again we are above nature, we've evolved beyond it and thats why we see good and evil, you cannot deny it, we have evolved to have "moral" mixing the spirit or the mind of humans with the body insticts, you cannot deny here that the human is still selfish and still obveys the laws of the world nature but we are still evolving, spiritually talking, at the end our spirits or minds or thoughts or intelligence whatever you may call it has lead us to be appart from animals afterall but we still have inherited in us our animal nature, in the actual society picture we can see that the moral basics are still in development, today most people would see a killing as something bad or evil, some others wont, maybe we will reach a point of universal morality or maybe we never will, all is in constant chage and we cannot foretell where human nature is leaded, after all it is a result of the enviroment, after the enviroment it comes the society which result lead us to human nature evolution, lets say that in 1000 years enviroment and society changes and that killing anyone you want is seen as good, lets hope not ok, but its the way the human psyche evolves and back then we would accept it, I know you may never see killing someone as good but the way you get raised determines you, determined by those two factors i mentioned. So my answer is that good and evil always exist the problem is that what is good for us changes and will change, as evil changes and will change.