The Furies were considered hideous in appearance. Like the Keres, they take the appearance of clawed women dressed in black and red with hair bristling of serpants. They carry whips and torches and are seen pursuing their victims.
Despite their negative interactions with humans, they were called Eumenides, or "kindly ones" in remembrance of their indulgence when Orest seek refuge after his motherís murder. They are sometimes represented by flies which harass their victims as remorse.
The Furies, or Erinyes in Greek, have an origin that is not completely known; they were born, it is said, from drops of blood that fell from Uranus after he was castrated by his son Cronus. It is also thought that they were the daughters of Mother Earth and Darkness, or of Cronus and Eurynome, or Cronus and Night.
Though originally there were an indefinite number of Furies, eventually the Greeks decided that there were three: Tisiphone (the avenger), Megara (the jealous), and Alecto (the unresting).
At first, the task of the Furies was to guard the entrance to Tartarus, to make certain that those who entered had atoned for their sins. Those who had not were rejected and had to wander as ghosts. They became better known for their responsibility as punishers of those who offended the Olympians, patricides, and perjurers.
Their main function was then to torment those who have committed a sin. Though origionally probably reserved for patricides, matricides, and those who broke their oaths, the Furies eventually would come to punish any sin. They would harass and injure her prey but not kill them.
They pursue wrong doers relentlessly, until death, often driving them to suicide. They would extend their torments into the underworld, cruelly lashing the offenders. The sight of them could drive one to madness.