the study of good and evil in philosophy is called ethics. ethics tries to explain why some actions are good and other actions are evil. it attempts to give all kinds of answers for how to tell evil from good. christians believe that at the second coming of christ, god will put an end to evil and the works of the devil- see the end of the book of revelation. in movies or tv series evil people are often called villains. political actions are sometimes viewed as evil such as authoritarianism, ableism or censorship. people disagree on why people do evil things. religious people may think that it is the result of listening to an evil being such as the devil or sin. others think it happens because of mental issues like anger, mental illness or revenge. certain types of behavior are also sometimes seen as evil such as killing or lying to be punished. sex crimes such as rape, hebophilia or pedophilia are also often seen as evil.