I was so happy ArenaNet added the Primeval outfit to the game, but unfortunately they didn't get the colors quite right!
"The Dervish's attire is a testament to the dual nature of the Dervish as both priest and warrior. Followers of this profession wear a robe to show their faith in the divine, bracers to demonstrate their prowess in combat, and a hood to mark their humility before the gods."
This look is great if you want to match your character with your Guild Wars 1 character. All you have to do is change the color of the first dye channel if you dyed it in GW1!