Edmund wondered when people had first began to misrepresent the relationship he had with his brother. They looked upon him like he was his brother's assistant or underling. High King over all Kings though Peter was, Edmund played errand boy for nobody (excepting of course Aslan whom he merely hoped held him in higher esteem than to ask such a thing of him). It seemed whenever people spoke to him it was in terms of Peter. They acted like he was only useful on his brother's behalf or in his brother's stead or as a support to his brother. Yet that he could tolerate. Those whom truly aggravated him were those who thought that not only was he subservient to his brother, but it was through Peter's cruelty. Edmund knew which element people's error regarding that more frustrated him, the notion that he would willingly take orders which he did not agree to he could endure, or that anybody would dare to doubt upon Peter's honour he could never.
Because Edmund Pevensie would follow his brother beyond the ends of the world. Willingly. And Edmund Pevensie, traitor once, would freely defy any mortal king at the bidding of his brother.