An FS is an artificial mind created by the Waterbe. The most notable FS is WATERBIUS (and its variants), though many other FSs have existed over the years and still exist.

FSs can also be divided into multiple subtypes, based upon their function and level of intelligence. Evolving FSs are those that are capable of modifying their own programming - the aforementioned WATERBIUS is an example of this type, as well as less sophisticated evolving FSs such as Nurakam, SunnevicaFS and Implexale.