Trolls, which have lived on Etheria since the Preternian era, have always preferred to live in rocky sections of land. But relations between them and the human population have always been strained. At one point in history, the Trolls managed to defeat the giant Spider of Crystal who had been summoned from another planet by an evil wizard. When the wizard failed to control the Spider, it began running amok until the Trolls managed to trap it beneath a mountain of rock.
When the Evil Horde came to conquer Etheria, the Trolls offered to help fight them alongside the other Eternian races. However, the human population, being fearful of the Trolls, refused their help. Therefore the Trolls retreated to Spikeheart, far away from the Horde as well as the humans.
After that, other races became even less trusting and more afraid of Trolls. Until even the very mention of the word Troll would cause revulsion in humans and Twiggets. For their part, the Trolls refused to trust any humans and preferred to keep to themselves in the rocky terrain of Spikeheart.
It was thanks to She-Ra that relationships between Trolls and other races began to improve. She first sought out the help of Agho the Troll King when searching for the fabled Crystal Castle. Some time later, Agho sent his most trusted lieutenant Grox to the Whispering Woods to ask for She-Ra's aid after Agho had had a premonition in a dream that the ancient enemy of the trolls, the Spider of Crystal, would soon escape from its stony prison. During this adventure, Grox and several members of the Rebellion, including Bow, Kowl, and Sprag the Twigget, learned to set aside their feelings of mistrust and made progress in forming friendship between all races.
When the Rock People migrated to Etheria because their own planet, Geolon, was about to be destroyed by its exploding sun, She-Ra asked King Agho if there was room for the Rock People to settle in Spikeheart. Having proven to be a loyal friend of the trolls, Agho did not refuse her request.