Naming of moons underworld, and Nix (a respelling of Nyx), mother of Charon, is the goddess of darkness and the night. Kerberos is a giant three-headed dog who guards the entrance to the underworld. The fifth moon is named for the river Styx that forms the boundary between the worlds of the living and the dead. The name of Eris's moon Dysnomia was suggested by its discoverer Michael E. Brown, who also suggested the name of the dwarf planet. The name has two meanings: in mythology Dysnomia (lawlessness) is the daughter of Eris (chaos). However, the name is also an intentional reference to
Pluto (mythology) . Jupiter got the sky, Neptune got the sea, and Pluto got the shaft." In Riordan's explanation, Hades "was more of a death god," but acquired his identity as a god of wealth among the Romans, along with a new name. Scientific terms derived from the name of Pluto include: Pluto (mythology) Pluto (Latin: "Plūtō"; , "") was the ruler of the underworld in classical mythology. The earlier name for the god was Hades, which became more common as the name of the underworld itself. In ancient Greek religion and mythology, Pluto represents a more positive concept of the god