The Greek Underworld is a mythical realm ruled by HADES, the god of the dead. It is also known as the House of HADES or the House of Death. HADES is the brother of Zeus and Poseidon, and is often depicted as a dark and gloomy figure. The Underworld is the place where souls go after death, and it is divided into several different regions, each with its own unique characteristics. HADES is the ruler of the Underworld and is responsible for judging the souls of the dead and deciding their fate.