Evil exists to glorify the good. Evil is negative good. It is a relative term. Evil can be transmuted into good. What is evil to one at one time, becomes good at another time to somebody else.
MenciusIf you love men and they are unfriendly, look into your love; if you rule men and they are unruly, look into your wisdom; if you are courteous to them and they do not respond, look into your courtesy. If what you do is vain, always seek within.
Mencius