Orpheus
Orpheus was the son of Calliope, the oldest of the nine Muses, whose name means "beautiful voice." In some sources, it is said that he was the son of Apollo, the God of music, poetry, medicine and fine arts, whereas in others, his father was Oeagrus, a Thracian King. Either way, being the son of a Muse, Orpheus inevitably inherited the musical gene and was well known for being able to tame wild animals with his music, his trademark instrument being the lyre. Orpheus travelled with Jason as an Argonaut on the ship Argo, in which we was able to drown out the menacingly beautiful songs of the Sirens with his own musical ability. He fell in love with the nymph Eurydice as soon as he set eyes on her, and shortly after, married her. After he lost his wife, Eurydice, a second time to the Underworld, he was so distraught that would just sit and sing to himself, alone and inconsolable. However, one night, a group of Thracian Bacchantes attacked him, dismembering his body and spreading his remains over the land; and it is said that his head was found on the isle of Lesbos after floating down the river.
Eurydice
Eurydice, a wood nymph, was the wife of Orpheus. Since ancient writers did not describe Eurydice in much detail of her life pre-Orpheus, the only accounts I can refer to are those which involve the couple together. Stunningly beautiful, Orpheus fell in love with her straight away, as she was amazed by his musical ability. The two were madly in love, but one day shortly after their wedding, Eurydice was wandering the river bank with her nymph friends, when she unknowingly stepped on a poisonous serpent, concealed in the long grass. She died instantly, and was sent directly to Hades and Persephone in the Underworld, where all the souls go after they die. She is temporarily rescued by her husband after he plays a moving song to the rulers of the Underworld, only to die again when Orpheus cannot resist turning to look at her. At the end of the passage by Virgil, she is pulled back to the Underworld in a wisp of smoke, her last words being "Good-bye. I am borne away. A limitless night is about me / And ever the strengthless hands I stretch to you, yours no longer," concluding one of the most tragic love stories of Classical Myth.
Hades
Brother of Zeus and Poseidon, and child of the Titans Kronos and Rhea, Hades was also referred to as the Latinised names 'Pluto' or 'Dis' by Ancient Romans. Just like four of his siblings, Hades was eaten by their father, Kronos, at birth, only to be freed when Kronos swallowed a stone (thinking it to be his newest offspring Zeus), and consequentially regurgitating all of his consumed children. God of the Underworld and Ruler of the Dead, Hades received his role after he, Zeus and Poseidon succeeded in defeating the Titans. The three drew lots to divide up the cosmos, Zeus becoming God of the Skies and Poseidon of the Seas, leaving Hades with the realm of the dead, the Underworld. Mesmerized by her beauty, Hades is well known for abducting Persephone, who became his unwilling wife. After feeding Persephone pomegranate seeds and compromising with her mother, Demeter, Persephone was forced to live with Hades as his queen in the Underworld for half of every year. When Orpheus petitioned for his wife back through his song, Hades was moved by his words, and it is sometimes said that Orpheus was able to appeal to his one weakness: his love for Persephone, causing him to shed a tear for the couple's plight. Hades allowed Eurydice to be free of the Underworld, but unfortunately did not give a third chance, as she was brought straight back to him after Orpheus broke Persephone's condition.
Persephone
Persephone, also known as 'Proserpina' by the Romans, was the Daughter of Zeus (King of the gods) and Demeter (Goddess of earth and agriculture). Persephone was stolen by Hades and kept as his wife and queen of the Underworld, leaving her mother mourning her disappearance and constantly searching for her. In her grief after discovering her daughter's whereabouts, Demeter refused to let the crops to grow, until an agreement was made with Hades. Persephone would be allowed to return to the upper world for half of the year, if the other half was to be spent with Hades. During the time she was with her mother, Demeter would allow the earth's plants and crops to grow abundantly, only to leave the earth unfruitful and barren when Persephone returned below. (This is how the Ancient Greeks explained the change in seasons.) In Virgil's account of Orpheus' journey to the Underworld, it is Persephone (called 'Prosperpine' in the source, because Virgil was Roman) who invents the condition that had to be met if Eurydice was to leave the Underworld. Although moved by Orpheus' heartfelt song, Persephone told Orpheus that he was not to turn to look at his wife until they reached the upper world, or she would once again belong to them in the Underworld.