What makes someone good and what makes someone evil according to the novel Grendel by John Gardner?

Is depends on who is saying it, but in my own opinion it mean a good person is someone who likely working to make earth more like heaven and less like hell. from my perspective both heaven and hell are real places, and people journey through each occasionally - - sometimes even during the same day. I'm the other hand, an evil person is kind of like a person that doing a lot of bad stuff in the community they are living about ...