|Day length||1 day|
|Year length||360 days|
|Polities||Serulus (CS Condominium)|
Serulus is an astronomical body that is the twin planet of Coracan. Serulus is in synchronous rotation with Coracan, and thus always shows the same side to Coracan, the near side.
Both Serulus's natural prominence in Coracan's sky and its regular cycle of phases as seen from Coracan have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, Serulus-based calendar systems, art, and mythology.
Serulus is home to many species that existed before the human presence intensified on Coracan around 33,000 years ago. These are often purple in colour.
The Conglomerate States, supported by several national governments, maintain manned research stations and settlements on the planet. Currently, fifty-seven people live on Serulus, 10 are staying for one year only, while the rest are staying indefinitely.
No children have been born on Serulus. Currently, the inhabitants of Serulus would have to jointly ask the full assembly of the Conglomerate States in order to be formally allowed to procreate; which would be a very public process.
- Main article: Conglomerate States Condominiums
According to the International Cosmos Treaty established by the Conglomerate States, all celestial bodies in Coracan's universe are CS Condominiums. This forbids the establishment of a military presence or land claims by any sovereign state on Serulus.
As a CS Condominium, any child born on Serulus (to date, none have) will automatically receive CS citizenship.