Susan and Edmund are sister and brother

Susan Pevensie and Edmund Pevensie are sister and brother, the second-eldest and third-eldest of the four children sent from London to the house of an old Professor during the war. Their relationship is defined by a fundamental opposition in character—Susan is cautious, sensible, and inclined to believe the evidence of her own eyes, while Edmund is spiteful, self-absorbed, and easily swayed by his appetites—and by a crisis of trust that nearly destroys their family before being healed through Aslan's intervention.

Identity and Temperament

Susan, the elder sister, is the most practical and risk-averse of the four. When Lucy first claims to have found a magical country inside the wardrobe, Susan is the one who physically checks the wardrobe and declares it "just an ordinary wardrobe," and she later tells the Professor that Lucy's story "couldn't be true—all this about the wood and the Faun." Edmund, by contrast, is described as someone who "could be spiteful," and on the occasion of Lucy's first return from Narnia he "sneered and jeered at her and kept on asking her if she'd found any other new countries in other cupboards all over the house." Where Susan's skepticism is rooted in a desire for order and safety, Edmund's mockery is driven by a mean-spirited need to belittle his younger sister.

The Crisis of Betrayal

The central rupture in Susan and Edmund's relationship occurs when Edmund, having secretly entered Narnia himself and met the White Witch, returns and deliberately lies to the others. When Peter asks him directly about Lucy's story, Edmund "gave a very superior look as if he were far older than Lucy (there was really only a year's difference) and then a little snigger and said, 'Oh, yes, Lucy and I have been playing—pretending that all her story about a country in the wardrobe is true. Just for fun, of course. There's nothing there really.'" This betrayal deepens the family's crisis: Susan and Peter, who had already doubted Lucy, now have their suspicions seemingly confirmed by Edmund's testimony. Susan later tells the Professor, "But Edmund said they had only been pretending," using his word as evidence against Lucy. The Professor's logical questioning—"does your experience lead you to regard your brother or your sister as the more reliable?"—forces Susan to admit that "in general, I'd say the same as Peter, but this couldn't be true." Her trust in Edmund's honesty, in this instance, outweighs her usual judgment of Lucy's character.

The Exposure and Estrangement

When all four children finally enter Narnia together, Edmund's earlier lie is exposed almost immediately. As they walk through the forest, he inadvertently says, "I say, oughtn't we to be bearing a bit more to the left, that is, if we are aiming for the lamp-post," revealing that he has been in Narnia before. Peter confronts him, and Susan is present for the dead silence that follows. Edmund, humiliated and angry, mutters to himself, "I'll pay you all out for this, you pack of stuck-up, self-satisfied prigs." From this point, Susan and Edmund are on opposite sides: Susan joins the others in trusting the Beavers and following the plan to meet Aslan, while Edmund slips away from the Beavers' house to betray them to the White Witch. When Mr. Beaver announces that Edmund has gone to the Witch, Susan protests, "Oh surely—oh really! ... he can't have done that," but then feels "suddenly quite certain inside that this was exactly what Edmund had done." Her instinctive defense of her brother gives way to a painful recognition of the truth.

Reconciliation and Restoration

After Edmund is rescued and Aslan speaks with him privately, the siblings are reunited. Aslan brings Edmund to the others and says, "Here is your brother, and—there is no need to talk to him about what is past." Edmund shakes hands with each of them in turn and says, "I'm sorry," and everyone, including Susan, says "That's all right." The narrative notes that "everyone wanted very hard to say something which would make it quite clear that they were all friends with him again—something ordinary and natural—and of course no one could think of anything in the world to say." This awkward, wordless moment of forgiveness is the true restoration of the sibling bond. Later, after the final battle, Susan and Lucy discuss whether Edmund should be told what Aslan did for him. Susan says, "Oh, surely not. It would be too awful for him. Think how you'd feel if you were he," showing a protective, empathetic concern for her brother's feelings that had been absent during the earlier conflict.

Narrative Role and Significance

Susan and Edmund's relationship functions as a key element of the story's moral and emotional arc. Their conflict—rooted in Edmund's betrayal and Susan's initial willingness to believe him over Lucy—creates the family division that the rest of the plot must heal. Susan's cautious, rule-bound nature contrasts with Edmund's reckless, self-serving choices, and their eventual reconciliation demonstrates that even a serious breach of trust can be repaired through honest apology and forgiveness. In the final coronation, Edmund is crowned King Edmund the Just, and Susan becomes Queen Susan the Gentle; their restored relationship as brother and sister is part of the harmony that characterizes the Pevensies' reign in Narnia.