Warlords
12 Achievements
200
Xbox 360
Duke
Have 4 balls of your colour in play Evolved game - Normal difficulty
10
How to unlock the Duke achievement in Warlords - Definitive Guide
Easy again. This achievement requires one player game, Evolved mode and Normal difficulty. You will propably get this during the game (about at wave 2 or 3). As it sais, you need to touch the balls as you have them to change their color to your color (blue usually). Just have 4 of the balls in blue and you get this achievement.
Every time you touch a ball in Evolved with your shield, that ball will become the same color as your knight until it touches a different shield from the opposing teams. In the levels, four balls are most likely going to appear as you progress, so this one's easy to get.