The Great Rebellion's greatest asset in their battle for freedom is She-Ra, He-Man's twin sister, who was previously a member of the Evil Horde, before defecting.
Etheria has often been linked to Eternia through the use of dimensional portals opened by The Sorceress, are descendants of Eternian immigrant colonist.
At a glance Etheria appears to be a beautiful, lush, fantastical world. In reality, it is a dystopia plagued by the tyrannical rule of the Evil Horde, which invaded the planet long ago and conquered it.
Etheria was founded by a group of beings known only as The First Ones. Their living spirits dwell in the Cavern of Fire, located in an underground kingdom, beneath The Crystal Castle. These beings were spiritual who connected to other planets in which it attracted the spirit of Grayskull of Eternia to unify, creating dimensional portals, where a caravan of Eternians immigrated to this planet, founding Etheria.
When the Horde invaded Eternia, Hordak was defeated by the King of Grayskull, casting Hordak and his allies into the dark field of Etheria, which had a direct passage to the planet, where Hordak takes his possession as the tyrant of the planet, Hordak uses the dark field to Have contact with Skeletor linking his fortress near the serpent mountain, his ancient throne.
The headquarters of the Horde is northwest of The Whispering Woods, where on the Horde's battlefield against rebellion, built its military barracks in the valley of shadows near the dark field.
Small Oak - A town where Horde scientists invented a shrinking serum.
Thaymor - A town near or in the kingdom of Bright Moon. It is the town Prince Adam first went to when he came to Etheria. It was also one of the first places where She-Ra organized a rebellion. It was the home of the Laughing Swan Inn.
Bluestone Palace - Although called a kingdom, the area around Bluestone palace is actually a protectorate of Mystacor and thereby ruled by Castaspella. The palace of Bluestone included a walled city.
Castle Bright Moon - A heavily fortified castle, which is the seat of power for a kingdom of the same name. It is ruled by Queen Angella, mother of Princess Glimmer. Queen Angella had magic powered by Etheria's two moons with which to defend the castle. This magic left the Castle vulnerable during eclipses.
Erelandia - Commonly referred to as King Duplis' Kingdom, this kingdom payed taxes to the Horde, but Prince Hazar secretly helped the rebellion. He was sent to the Mines of Mondor on the planet Krytis for his crime. After his son was rescued by She-Ra, King Duplis agreed to help the rebellion.
Greenvale - an enclave kingdom within Mystacor made up of King Gruff and his blue furred leporidious species.
Halfmoon - Underground kingdom inhabited by the Magicats.
Mystacor - A magical kingdom ruled by Castaspella. The seat of power was a Castaspella's Enchanted Castle, which set atop a floating island. Many of its people are magically endowed. For a short time it was ruled by Mortella.
Beast Island - A dangerous jungle island that was seemingly made up mostly of rock and the fossilized skeletons of huge beasts. It was home to the Horde's main prison where it once held He-Man and the Dragon Sorrowful. Grizzlor was often in charge of the island.