Although Kay is the Wart's brother, he is his opposite (or foil) in many ways. One of the first descriptions of Kay informs the reader that he is "too dignified to have a nickname," and it is Kay's yearning for chivalric dignity that serves as the foundation of his character. He disregards the advice of those he deems lower than himself (such as Hob), despite the fact that he sometimes makes himself appear foolish in the process (as he does when disregarding Cully's advice about hawking). Kay is determined to become a knight, but lacks one of a knight's most important characteristics: humility. After killing a griffin, for example, Kay revels in his father's mounting the head and placing a sign under it reading, "KAY'S FIRST GRIFFIN." Kay also has a tantrum when the Wart refuses to tell him about one of his lessons with Merlyn, and releases his envy in the punches he throws at his younger brother.
White emphasizes Kay's childishness at the novel's end, where Kay arrives in London to attempt to pull the sword from the stone. Naturally, Kay thinks he has a very good chance of doing so — an idea stressed when he thinks, "anybody who does not go for a tournament like this will be proving that he has no noble blood in his veins." He barks orders at the Wart to fetch his sword (as if the Wart were his slave rather than his squire) and even attempts to take credit for the Wart's pulling the sword from the stone. However, even a person as envious as Kay cannot deny the truth of the Wart's destiny, and must acknowledge him as King Arthur along with the rest of England.