Rose and Dimitri are the best guardians out there. When Lissa takes the throne, she needs to select her first guardian, the one who will always be by her side. Her first choice was obviously Rose. Problem was that the council was pushing for a guy called Dimitri to be her guardian because he has more experience than her and well looked more intimidating. Nonetheless they were both very skilled. In order to decide which of them would take the most wanted position in the guardian world, they'd have to compete against each other.