Jealousy
One of the central themes in the book is jealousy, and it is exhibited by both Edmund and Charles. Edmund is jealous of the idea of Charles before he even meets him; he doesn't want to share Warings with a newcomer, an outsider, and he does not think that someone should be able to come into the house and the family and get equal rights to everything when Edmund is a descendant of the house's original owners, whereas Charles is not.
Charles is jealous of Edmund because he already lives at Warings. Although Charles does not like the house at all, he is jealous that Edmund seems to get favorable treatment within it. He is also jealous of the children he makes friends with who do not live at Warings and who do not have to live with Edmund because their lives seem far more normal.
Bullying
Edmund is a bully, but in a quite alarmingly sociopathic way. He seems to take great pleasure in tormenting Charles, and making his life completely miserable with his mental brutality. He is also an extremely manipulative bully because he does not bully in a physical way. If he did, Charles would be able to go to his mother and show her a bruise, or a scratch, something that would be evidence of Edmund's bullying. Emotional and mental bullying prevent him from doing this. The extent of the bullying is so great that Charles decides suicide is a preferable alternative to spending the rest of his childhood with Edmund as his step-brother.
Parents Who Don't Know Their Children
Both Edmund's father and Charles' mother think that they know their boys. They also believe that the two are getting along wonderfully and are pleased to have a playmate in the home. Edmund's father feels that his son is lonely, and this assumption is correct, but it is not a brother for whom Edmund pines; Edmund is lonely because he misses his mother and because he gets no tenderness or empathy from his father.
Charles is lonely because he never seems to be anywhere long enough to make friendships that can last. He is a gregarious child but as he and his mother move around so much he finds making friends impractical. He longs for stability, not a brother.
Edmund manages to fool both his father, and Charles' mother, into thinking that he is devastated by Charles' death. Charles' depression and fear of Edmund has also go unnoticed. Both parents believe that they know their children well but both have little to no idea of what they are actually feeling, or what they are really like.
