Sentry
 By Fredric Brown
 He was wet and muddy and hungry and cold
 and he was fifty thousand light-years from
 home.
 A strange blue sun gave light, and gravity,
 twice what he was used to, made every
 movement difficult.
 But in tens of thousands of years this part of
 war hadn't changed. The flyboys were fine with
 their sleek spaceships and their fancy weapons.
 When the chips are down, though, it was still
 the foot soldier, the infantry, that had to take
 the ground and hold it, foot by bloody foot.
 Like this cursed planet of a star he'd never
 heard of until they'd landed him there. And
 now it was sacred ground because the aliens
 were there too. The aliens, the only other
 intelligent race in the Galaxy-cruel, hideous,
 and repulsive monsters.
 Contact had been made with them near
 the centre of the Galaxy, after the slow.
 difficult colonization of a dozen thousand
 planets; and it had been war at sight; they'd
 shot without even trying to negotiate, or to
 make peace.
 Now, planet by bitter planet, it was being
 fought out.
 He was wet and muddy and hungry and
 cold, and the day was raw with a high wind that hurt his eyes. But the aliens were trying to infiltrate and every sentry post was vital.
 He stayed alert, gun ready. Fifty thousand
 light-years from home, fighting on a strange
 world, and wondering if he'd ever live to see
 home again. .And then he saw one of them crawling toward him. He drew a bead and fired. The alien made that strange horrible sound they all make.
 then lay still
 He shuddered at the sound and sight of the
 alien lying there. One ought to be able to get used to them after a while, but he'd never been able to. Such repulsive creatures they were, with
 only two arms and two legs, ghastly white
 skins, and no scales. 
 (How far away from home is main character in this story)
 (according to this story describe what 
 You think the main character looks like)