What is evil? why does evil exist?
Evil is concept used to describe suffering. While suffering truly exist, there is no such thing as an evil intention. Evil is never an end but always a mean to achieve something. It is devoid of spiritual nature and only exist in the material world. There is no evil spirit such as Satan because consciousness is always a manifestation of the universal absolute which is god. It is easy to judge an action and consider it to be evil, but once the motivations are understood, we realize that the categorization of the actions as evil was misguided by an illusion from the lack of understanding of the underlying mechanisms. The only sources of evil lies in ignorance and passion (which is purely material).
When we don't know their consequences, we may engage in actions that may result in suffering. Sometimes it's because of the lack of empathy (which is a form of ignorance, sometimes it is the lack of experience). A child could do quite evil things just because of ignorance. Some people may even lack the ability to perceive other people's suffering or even their own suffering. In the most extreme cases of sociopathy, some other people may even genuinely desire to make people suffer, but that desire of suffering is always a misguided inefficient and clumsy mean to achieve a higher good. When a hurricane destroys a village, is the hurricane evil? When a tiger hunts its prey, is the tiger evil? Is the flu virus evil? Are corporations evil when they abuse their employees and vendors?
Sometimes we know one of our action to be evil but we choose do it anyways. In such cases, there is an internal conflict between consciousness and passion. If passion wins, then the actor of the evil act is not consciousness but passions. Therefore, consciousness is never the source of evil. Even when we consider consciousness to be the source of evil, for that to be the case, consciousness must be insufficient or distorted.