The Juggernaut-class Shivan Dreadnought that ambushed and destroyed the GVD Psamtik during an attack on Shivan gas miners. While it is unknown how many exist, over eighty have been seen when these ships destroyed the Capella star, causing a supernova. The Blue Lions' leader, Shawn Farrell, perished in the explosion, protecting fleeing GTVA transports from Shivan attack as they escaped out of the system. This ship was also responsible for the destruction of the GTVA Colossus. Previously, the largest Shivan ship known to the GTVA was the Ravana. There is no known Shivan ship larger than the Sathanas.
The word itself is, very loosely, another term for Satan.
All other intelligence regarding the Sathanas has been classified level Phi.