The Field of Arbol is the star system that includes Megacrossover Earth. It contains eight planets, all with some form of life, and is ruled over by the Oyeresu, powerful eldila appointed by the Elder Council to watch over the system's native inhabitants, especially those from Earth.
Sol (Arbol in Old Solarian) is the star at the center of the Field of Arbol. It is inhabited by djinns, plasma-based entities that are able to survive its heat.
Mercury (Viritrilbia) is the nearest planet to the Sun. It does not have any native sapient life, although some djinn and eldila have made it their home.
Venus (Perelandra) is a perpetually tropical planet surrounded by a thick cloud. It is home to humanoid beings known as the Torlindri who are known for uplifting native species.
Earth (Thulacandra) is home to humans, along with a variety of supernatural beings that have managed to hide away from human society. For many millions of years, it was under quarantine due to the influence of Melkor, "the Bent One." In the 22nd century, it became one of the founding members of the United Federation of Planets.
Mars (Malacandra) is home to numerous sapient beings, including the Red and White Martians, the Seroni, and the Hrossa. Originally, the planet was full of life, but it has become a desert world tens of thousands of years ago due to the workings of Melkor, with many inhabitants migrating to other worlds.