Greek underworld his duty was to bring these souls to the underworld and no one would persuade him to do otherwise. Cerberus (Kerberos), or the "Hell-Hound", is Hades' massive multi-headed (usually three-headed) dog with some descriptions stating that it also has a snake-headed tail and snake heads on its back and as its mane. Born from Echidna and Typhon, Cerberus guards the gate that serves as the entrance of the underworld. Cerberus' duty is to prevent dead people from leaving the underworld. Heracles once borrowed Cerberus as the final part of the Labours of Heracles. Orpheus once soothed it to sleep with
Pluto uses "Sao Diêm Vương", which was derived from the Chinese term 閻王 (Yánwáng), as "minh" is a homophone for the Sino-Vietnamese words for "dark" (冥) and "bright" (明)). Some Indian languages use the name Pluto, but others, such as Hindi, use the name of "Yama", the God of Death in Hindu and Buddhist mythology. Polynesian languages also tend to use the indigenous god of the underworld, as in Māori "Whiro". Once Pluto was found, its faintness and lack of a resolvable disc cast doubt on the idea that it was Lowell's Planet X. Estimates of Pluto's mass were revised downward