The Colors of Elberia; book 1 of The Black Blade trilogy

The Rolak Plains had been roiling with the colors for months. Evil creatures had been attacking the Havens since the disturbance had started. Niethon and a band of color guards had gone into the plains to see if they could determine the source of this evil. Only Niethon had returned, but he had gone quite mad and would not speak. Only after a couple of weeks did he begin to remember. As he awakens, he finds he can trust no one, not even those he used to consider friends. He believes the only chance he has of saving the Havens is to warn Hetta, the yellow tarek and the woman he loves, of the impending doom.