Conscience is the thing within that keeps Dick from lying, cheating, stealing, or killing. It forms the psychological lines that Dick won't cross or the cultural taboos that direct his behavior.
An antagonist doesn’t have to be without conscience. He can truly believe in his cause or plan and at the crisis point realize that he has been doing something wrong. He can know from the beginning that he is doing something wrong, but justify it until the crisis comes along and he can’t anymore. He can exit the stage steadfast in the belief that he was correct.
Shame can serve as strong motivation. Shame creates that burning sensation in the chest. It can make Dick regret something he has done and apologize for it. Lies and betrayals, large and small, can lie heavily on his conscience. Shame can inspire Dick to do something noble to make up for his mistake.
Shame can have the opposite effect. Jane can feel so full of shame that it sends her into a death spiral of low self-esteem that forces her further into addiction or crime. It can so damage her self esteem that she doesn’t see the point in trying to be any different. Trying to drag Jane back to a sense of balance can be impossible.
Shame can create small, subtle conflicts within a psyche, a marriage, a friendship, a social club, or a work group.
Characters can accept blame for things they didn’t do either because their self esteem is low or because they want to protect someone else. They can take responsibility for things they shouldn’t. A crisis of conscience can be a story problem or a story solution. It can be a protagonist’s personal dilemma.
Conscience can drive different characters in different directions. Conscience can send Dick to war and make Jane a conscientious objector.
On the dark side, are characters who lack conscience. Psychopathy and sociopathy are similar disorders. Both are considered antisocial personality disorders. Some consider sociopaths less in control, more anxious and easily agitated and more likely to act up in public. They are often homeless because they can’t do what it takes to live in normal society. A psychopath is considered calmer, more secretive and manipulative. They can be charismatic and charming, hiding their pathology with a veneer of health. They don’t feel remorse or guilt but are aware enough of what the appropriate human responses are that they can mimic them. They both mean trouble and make chilling antagonists. However, they tend to be one-dimensional. An argument could be made that they have been overused.
Characters are rarely one-hundred percent good or evil. Crafting them with shadow and light makes them more interesting. Internal conflict enriches the story. Wrestling with their choices creates tension.
For more about how to craft characters, pick up a copy of Story Building Blocks II: Crafting Believable Conflict, available in paperback and E-book and Story Building Blocks: Build A Cast Workbook, available in paperback and E-book.