I didn't know how to call these Greek deities as a group... I guess it's ok to mention the Underworld because all of them belong there in some way. I decided to draw something related to the dead for Halloween, but not specially scary stuff
From left to right, up to down:
The Erinyes (The Furies): goddesses of vengeance, "those who beneath the earth punish whosoever has sworn a false oath". In the Greek tradition they are three: Alecto, Megaera and Tisiphone.
Hades and Persephone: the king and queen of the underworld... I really like this couple
Melinoe: possibly their daughter, goddess of the ghosts and the offerings to the deceased.
Hecate: ancient and powerful goddess related to magic, necromancy, wilderness and witchcraft.
Hope you like them