Conflicts between characters are common in most literature. There is usually a protagonist and an antagonist, and the protagonist may often be a heroic figure whereas the antagonist may often be a villainous figure. These conflicts between characters are familiar to us even as children. Little Red Riding Hood is in conflict with the wolf, Jack is in conflict with the giant, and Cinderella is in conflict with her wicked step-mother and step-sisters.
Whenever discussing or analyzing this type of conflict between characters, it is useful to consider the source of the conflict. Sometimes it can be as simple as one character being good and the other bad, but often there might be more interesting, nuanced reasons. In Shakespeare's plays, for example, there is often a conflict between characters who are fighting for power, or, perhaps even more interestingly, for no good reason at all. There is a conflict between King Lear and two of his daughters because all three want more power than they have. There is conflict between the families of Romeo and Juliet for no good reason other than the feud between them which has become something of a tradition.
Many conflicts in literature are moral or ethical conflicts, between good on the one hand and evil on the other. For these conflicts, it might be interesting, in any written analysis or discussion, to think about what exactly we understand good and evil to mean. To be good often means to be altruistic and kind, whereas to be evil often means to be self-serving and cruel. When analysing a conflict between good and evil it might also be interesting to consider what it is that makes one person good and another evil. Is a person inherently one or the other, for example, or is a person made either good or evil by the society into which he or she is born?