Hades is the lord of the dead and ruler of the nether world, which is referred to as the domain of Hades or, by transference, as Hades alone. He is the son of Cronus and Rhea. When the three sons of Cronus divided the world among each other, Hades was given the underworld, while his brothers Zeus and Poseidon took the upperworld and the sea respectively. For a while Hades ruled the underworld together with Persephone, whom he had abducted from the upperworld, but Zeus ordered him to release Persephone back into the care of her mother Demeter. However, before she left he gave her a pomegranate and when she ate of it, it bound her to the underworld forever.
Hades sits on a throne made of ebony, and carries a scepter. He also has a helmet, given to him by the Cyclopes, which can make him invisible. Hades rules the dead, assisted by various (demonic) helpers, such as Thanatos and Hypnos, the ferryman Charon, and the hound Cerberus. Many heroes from Greek mythology have descended into the underworld, either to question the shades or trying to free them. Although Hades does not allow his subjects to leave his domain, on several occasions he has granted permission, such as when Orpheus requested the return of his beloved Eurydice. Hades possesses the riches of the earth, and is thus referred to as 'the Rich One'. Possibly also because -- as Sophocles writes -- 'the gloomy Hades enriches himself with our sighs and our tears'. Of all the gods, Hades is the one who is liked the least and even the gods themselves have an aversion of him. People avoided speaking his name lest they attracted his unwanted attention. With their faces averted they sacrificed black sheep, whose blood they let drip into pits, and when they prayed to him, they would bang their hands on the ground. The narcissus and the cypress are sacred to him.

Hades' symbols:

Bident

The Realm Of Darkness

Cerberus