For questions in which a force or entity strongly opposes traditional moral or ethical views.
An entity or force is deemed "evil" if it strongly opposes traditional moral or ethical values. Many questions include something that is "pure evil", an abomination that goes out of its way to make the world around it unpleasant for others.
It is important to remember when creating something "evil" that morals are subjective.
Your "good" might be my "bad", and vice-versa, depending on our backgrounds and societies. This is especially true when designing very foreign or alien cultures - so be careful what you call evil!
In other words, morals can be blue and orange, not just black and white.