Evil characters seek the greatest good for themselves at the expense of anyone who gets in their way. Few evil being actually seek to spread death and destruction. People or situations that disrupt an evil character's plans or goals are mere hindrances that should be overcome at the first availability. If someone gets harmed in the process, that is just too bad. Most evil characters simply do not see their actions as evil or disruptive. Many evil characters will try to rationalize what they do as not being evil, even to the point of deluding themselves into believing that they are good (or neutral). These characters may even perform good deeds (but they always have an ulterior motive or some secret initiative). It is difficult to tell when someone is actually evil unless they are one of the few that upholds evil as a "virtue".
Evil is a social and cultural value. What one culture views as abominable (like slavery, gender oppression, etc.), another may view as normal and expected. A character's alignment is gauged by what they believe. The motives behind their actions is more important than what the culture sees as the "right" behind what they do.
