There was an unspoken rule that you didn't want to interact with the goblins in the woods. Whoever had made this world had plopped a few goblins down in it, and all they did was cause chaos. There weren't a lot of them, and while they were obviously intelligent, whatever culture the species had had on its home world had been left behind. In practice this meant the goblins were crude, savage, even bloodthirsty at times.
They would set up traps for humans who came too close to their territory. Sometimes they would delight in torturing those they caught, even sending them back scarred and broken as a warning. Other times death would come swiftly, the goblins deciding some particular human would taste good filetted and fried.
Not much was known about them in fact. They seemed to have some kind of basic language, the ability to coordinate, pass on skills in trap making. But they never developed farming or domestication like humans, and their numbers were always small. The humans, for their part, were happy to leave the goblins alone. It was just known that the wilderness was full of dark terrifying things, that were best not interacted with.
Every now and then some particularly stupid (usually young) human would decide it was a good idea to try to kill a goblin. This was always a terrible mistake. Goblins were much less coordinated than a human tribe, but individually they were much smarter than an average human. In addition, they had the strength of several adult men. Combined with a territory infested with cruel traps of all description and it was clear attempting to kill a goblin was suicide.
Over time, the humans would slowly encroach on the dark forests where the goblins lived. More land was needed to farm for the growing human population. For all their natural advantages, Goblins simply didn't breed quickly, and tended to live much longer lives than humans. Sometimes hundreds of years. Perhaps on their home world, the goblins had time to build up a culture that stood the test of time, but on earth that was not a luxury they had. Individually outmatched by goblins, en masse humans were far superior. There was precisely one war between humans and goblins, and it lasted all of a week.
In the end, their bodies weren't even preserved for posterity. There was no one to say "Goblins once existed. We know this. Here are their bones. Here are the tools they used to dig up moles. Here are the rope traps they used to kill our ancestors. Here are the words we heard them use. Here are the beads they used to tie into their hair. Here are the rough beginnings of the culture they were to build if we'd given them the chance."
But at the the humans killed the goblins, writing did not yet exist. Stories were passed on, but no records were kept. Only their name remains, passed down from prehistory. Goblin.
One day, when your children reach the stars, they may find the world of the goblins. A culture thousands of millenia old, slowly grown like the gnarled roots of a sequoia. Represented on Earth only by a few stolen infants who grew up without knowing the heritage they'd been born into. Forced to grow that tree again from a seedling, but not given nearly enough sunlight or water.