Pluto was originally the Roman god of certain metals, but because these materials are mined he also took on the role of God of the Underworld. The name is the Latinized form of Greek Πλούτων (Ploutōn), another name by which Hades was known in Greek mythology, possibly from the Greek word for wealth, πλοῦτος (ploutos). He is believed to be the lord of all the metals, jewels and riches that lie under the surface of the Earth.
Pluto, son of Saturn and Ops, assisted Iupiter in His wars, and after victory had crowned their exertions in placing His brother on the throne, He obtained a share of His father's dominions, which, as some authors say, was the eastern continent, and lower regions of Asia; but, according to the common opinion, Pluto's division lay in the west. He fixed his residence in Spain, and lived in Iberia, near the Pyrrenees mountains.
His whole domains are washed with vast and rapid rivers, whose peculiar qualities strike horror into mortals. Cocytus falls with an impetuous roaring; Phlegethon rages with a torrent of flames; the Acharusian fen is dreadful for its stench and filth: nor does Charon, the ferryman, who wafts souls over, occasion any less horror; Cerberus, the triple-headed dog, stands ready with open mouths to receive them; and the Furies shake at them their serpentine locks.
He is usually represented in an ebony chariot, drawn by his four black horses, Orphnaeus, Aethon, Nycteus, and Alastor. As god of the dead, keys were the ensigns of his authority, because there is no possibility of returning when the gates of his palace are locked. Sometimes he holds a sceptre, to denote his power; at other times a wand, with which he directs the movements of his subject ghosts. Homer speaks of his helmet as having the quality of rendering the wearer invisible; and tells us that Minerva borrowed it when she fought against the Trojans, that she might not be discovered by Mars. Perseus also used this helmet when he cut off Medusa's head.
The widely accepted story about Hades and Persephone was also told of Pluto and Proserpina in Roman myth. Pluto and Proserpina are almost exact replicas of their Greek equivalents, as the Romans' ideas about the spirits of the underworld were very vague before adopting Greek mythology. Venus, in order to bring love to Pluto, sent her son Amor, also known as Cupid, to hit Pluto with one of his arrows. Proserpina was in Sicily, at the fountain of Arethusa near Enna, where she was playing with some nymphs and collecting flowers, when Pluto came out from the volcano Etna with four black horses. He abducted her in order to marry her and live with her in Hades, the Greco-Roman Underworld. She is therefore Queen of the Underworld.
Notably, Pluto was also her uncle, being the brother of her parents, Iuppiter and Ceres.
Ceres vainly went looking for her in any corner of the Earth, but wasn't able to find anything but her daughter’s small belt that was floating upon a little lake (made with the tears of the nymphs). Ceres angrily stopped the growth of fruits and vegetables, bestowing a malediction on Sicily. The plants died, and it became cold and dark above ground. Ceres refused to go back to Mount Olympus and started walking on the Earth, making a desert at every step. While Proserpina remained in captivity, Ceres wept, and nothing could grow or be harvested. The people of the world were dying, and prayed to Iuppiter for help. Worried, Iuppiter sent Mercury to order Pluto to free Proserpina. Pluto would have obeyed, but by then, she had eaten six pomegranate seeds, whether of her own accord or through Pluto's trickery. Having tasted the food of the underworld, she could not leave, but when Iuppiter ordered her return, Pluto struck a deal with him. He said that since she had stolen his six pomegranate seeds, she must stay with him six months of the year, but could remain aboveground the rest of the time. For this reason, in spring when Ceres received her daughter back, the crops blossomed and flowers colored in a beautiful welcome to her daughter, and in summer they flourished. In the autumn, Ceres changed the leaves to shades of brown and orange (her favorite colors) as a gift to Proserpina before she had to return to the underworld. During the time that Proserpina resided with Pluto, the world went through winter, a time when the earth was barren.
Although Hades was seen as somewhat merciless, Pluto was worshipped by the Romans for some of his kinder attributes. Although Hades took a central role in many Greek myths, Pluto was not as much of a general focus.
Pluto is also the god of the dead, terminally ill, and those wounded in battle.