Whatever the theory behind the origin of this cosmos may come to be true, it is definite that man exists on this earth with his most perfect form as a master of technology.
Now if god created this world why would he do anything wrong to man by creating evil and if nature is the authority why should it create evil or bad or do anything that is evil in itself. Then the question arises who created evil? There are two possibilities of the creation of evil.
(1) Nature has both the forces; that of creation and of destruction in it. The force of creation cannot be evil but the force of destruction can act as evil. For example, a lion when hungry preys on another animal and eats it. This is an act of survival for nature but when it kills some infant or man then it is considered as an act of evil and the lion becomes the evil doer.
(2) Man created the society to bring peace and harmony in the relationships among its fellow men. Code of conduct was defined. And things when done in accordance with this code of conduct it was considered as a good behavior but as soon as this code of conduct was breached and things went wrong in the society it was considered as an act of evil. Religion came to take command of the behavior of man in the society. And it actually defined evil from time to time, changing its views from time to time. The person who acted, as defined by religion as evil action, was the evil doer. For example, when Ravana kidnapped Sita he became a source of evil in the society.
(3) Man living in the society can also act an evil. He is bound to his senses and needs, which can force him to act in a way that can cause harm to others, thus he can become evil by himself.
The right of one person becomes the duty of another but how many of us think in this manner and so evil prevails in this human society.
When evil is not definable in terms of the action of a person then nature and the circumstances in which man is caught is taken together to be evil. Thus evil can be said a source of threat and fear to prevent man from doing wrong to other fellow men in the society.
It is really difficult to say who created evil but it is very important to curb it from spreading in the world in whatever form it may be - terrorism, injustice, killing, infanticide, massacre, etc. Is it so difficult to follow the motto of "Simple Living High Thinking."