Hades (play /ˈheɪdiːz/; from Greek ᾍδης (older form Ἀϝίδης), Hadēs, originally Ἅιδης, Haidēs or Άΐδης, Aidēs (Doric Ἀΐδας Aidas), meaning "the unseen" was the ancient Greek god of the underworld.
Pluto 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 as a place.
Comments: Hades vs Pluto (mythology)