During the One Year War, Gato was a famous ace pilot, dreaded by Federation soldiers as the "Nightmare of Solomon." During the last battle of the war he grudgingly agreed to leave the battlefield with Delaz, living to fight another day rather than going out in a blaze of glory. Now this master warrior lives only for the resurrection of the Zeon cause, displaying little emotion other than contempt for the incompetence of his Federation foes. While Kou becomes obsessed with avenging Gato's theft of the Gundam GP02A, this rivalry is decidedly one-sided - it's almost beneath Gato's dignity to acknowledge a clumsy Federation rookie as his adversary.

(Source: Gundamofficial.com)