As stated on the main page, Cassandra is a large moon orbiting a gas giant named Ouranos. It orbits a K class star inside it's habitable zone. It was created by a god named Cinder, who didn't realize it was condusive to live and was thus left abandoned for hundreds of millions of years.
Cassandra is one of four large moons, and is the second in orbit from its planet. Like all other large moons, it's tidally locked. Only one side of it ever faces Ouranos. A single orbit takes around 46 hours. The two other moons that orbit closest to Cassandra exert tidal forces on it, creating something akin to the tides on earth as well as causing significant volcanic activity. The sulfur expelled by these volcanoes is a definite threat to Cassandra's already stressed ecosystem.