The desert sand has an eerie property. It enters anything. You live in the desert and you know that your teeth will grind sand, and your lungs will breathe sand, and your computer screen will be reddish because of the sand. The oil on your heavy machine gun is textured with sand, and the scratches on your armor are more because of the sand than of the enemy.
You live in the sand, you feel the sand crackling under your boots. Even now, in this mad race, you run, sweat trickling on your neck, filtering beneath the plasteel armors that follow your every move. The HMG weighs on your shoulder, but you don't feel it anymore. You don't feel anything else, as the first Xeno comes into your sight. There is nothing, except you, it...
...And the roar of a hundred thousand fans screaming their lungs out as your majestic stride brings the ball closer and closer to the touchdown. The opponent basher, a gigantic Xeno, tries in vain to grab you, but a twist to the right frees your path from its impending shadow. Just a few meters more, and the crowd will scream our name in joy!
After years of sterile and violent war, the alien leaders decided to approach their human counterparts in a different way. As the armed conflict brought precious little advantage to either parts, the Xenos proposed to use an old and honored galactic tradition: any conflict can be resolved in a truly sportsmanlike way - which also has the advantage to appease pacifists and warmongers alike. The Galaxy Ball is a rough and brutal sport, vaguely reminiscent of American Football, in which the teams face off with armors, weapons, and at least one ball (usually more). Galaxy Ball is immensely popular in the whole galaxy, because - as they say - if you can't tackle 'em, shoot 'em!
Henceforth, a team was gathered choosing the best men and women the Agency could offer. The rules and principles of the game were analyzed and elaborated, and the Xeno even allowed their trainers to come and instruct the "Earthlings". They are confident in their victory, but have yet to face such a motivated opponents as the human race!