Sometime in the past, the planet was once covered in water, and it was warm enough that it was not frozen over yet. The society of Mer-aliens had contact with interstellar travelers. After the Baku crashed into the planet and blocked the largest thermal vent with its body, the temperatures dropped, freezing the surface, and only the area around the Baku remained warm. This forced the natives to live close by on the ocean's bottom. Queen Luxia investigated the crashed creature and became brainwashed from eating the material growing on its body. As more Mer-people consumed the "food" at her command, they too became brainwashed and worshiped the Baku as the "giver of life" who kept them "safe and warm". Whenever commanded, either for a perceived crime or otherwise, a Mer would be sent to the Baku by the queen under the belief of being "returned to the giver of life." In truth, the Mer would be consumed by the Baku as food.
After Team Voltron is split apart in the corrupted Wormhole by Haggar, Lance and Hunk crash into the frozen waters of the planet and are invited to stay with the Mer. Hunk becomes brainwashed by the food, while Lance is rescued by Mer rebels who claim Queen Luxia is the source of the mind-control. Lance discovers the truth about the Baku and frees the queen and Hunk from its control, then defeats the Baku alongside Hunk. The Mer return the favor by assisting them in contacting the rest of the Voltron team.
The frozen planet so called because it is almost entirely frozen to its core. The ice has grown so large that it reaches planet's outer rings, which have become a solid sheet of ice encircling the planet. The southern region is a giant mountain of pointed ice protrusions, while the northern region has scattered protrusions and a thinner ice surface. Underneath the ice is a deep ocean covering the planet. The natives live gathered at the bottom of the ocean around the Baku, surrounded by rocky caverns and aquatic life. There are several alien fish and alien jellyfish that live in the ocean. The jellyfish can appear small and instantly grow to frighteningly large sizes when startled. There are also large, alien seahorse creatures the native Mer society uses as transportation and beasts of burden along with massive alien manta rays.
- For more information, see the Mer article.
The Mer aliens are an intelligent aquatic race similar to the mythological mermaids of Earth. They live in a large underwater village ruled by Queen Luxia who lives in the prominent palace overlooking the village. The palace is guarded by male Mer and the queen has several female servants. The Mer utilize animal species around them for various uses in daily life.
Kept inside a large clam is an energy beacon in the form of a pearl that can project a beam of energy into space. The beacon can be used as a signal to guide nearby travelers to the planet and can project an image of spacecrafts in the area. The beacon was once used in the past to communicate with travelers in space before the Baku overtook the minds of the Mer.
- The name of the planet is unknown.
- The name of the race inhabiting the planet is unknown. The term "Mer" or "Mer aliens" is not present in the canon. "Mermaids" is used by the aliens themselves about some of their own kind, but it is not clarified if they are only referring to one gender of the race. (Specifically, the female servants in the palace sent to the Baku.)