In Stone House Farm the rejected fiancee of the hero and an ex-husband of the heroine want retribution. Not getting what she wants (his wealth and prestige) leads the ex-fiance to try to kill the man who didn't want her, and the ex-husband tries to get more money from his ex-wife.
In Rogue's Rules, there are two evil characters. One is Morgan Dachs, who, to save his life and ship, traded thirteen fellow crewmembers to a slaver. Morgan's uncle-in-law, Durrant Rosche, uses the powerful Dachs name, and their wealth, for his personal gain. While they were bad, in Angels Tread readers learn it was another powerful person who was controlling them. And Admiral Ries Vaughn used his rank and power to get whatever he wanted.
In Constantine's Legacy, a high-ranking priest has a fraudulent document made that says Emperor Constantine the Great gave the Church his lands in Italy when he moved the court to Byzantium. He ends up trying to kill the story's hero who knows the truth.
The judgment on the good or evil of a person depends on many things. The world's human populations are complicated as well as their history. What's good in one country can be evil in another. During their early development, people lived in tribes whose individuals helped protect each other, but often annihilated other tribes. Our history shows this tendency continues between certain populations and countries. Individuals have the same tendencies. How each person is raised and their mental outlook has a great influence on whether they are considered a good or bad person. And certainly, like the Earth, they have polar opposites that can switch from good to evil or vice-versa for their own survival.
Part of writing is showing how a character's history and his or her outlook will develop how they can become evil.
On the other hand, I have witnessed strangers bestowing great kindness. I was once ringing up a customer's bill, but her card wouldn't cover the cost. The man in line behind her said he'd pay it. And he did—over eighty dollars. This works in writing stories, too, as it shows how a character's behavior lets the reader judge their goodness or evilness.
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