Courage
Despite their youth, the protagonists of Prince Caspian define themselves by their courage and willingness to do what is right. They fight for what they believe in, working against the corruption in Narnia. In contrast, their enemies are constantly stabbing people in the back, and having people killed for them in cowardly ways, instead of fighting for themselves
Religion
C. S. Lewis' protagonists represent what he saw as the ideal Christians: just, loyal, kind, and grave. Aslan himself represented Jesus in the world of Narnia, referring to God as his "Father across the sea". Religious imagery and morals push the plot of Prince Caspian, assuring readers that character who portray its ideals will find victory.
Nature
Nature is a theme that persists throughout the chronicles of Narnia, from the idealistic land of nature created by Aslan to the corruption of Prince Caspian, where the humans fear the nature of the woods and the old world of the Narnians. Caspian and his army have a respect for nature that his enemies do not understand but that eventually leads them to victory.
