Witches of Hades

This are the Witches of Hades.
Pearl, the White Witch at the South.
Zaphire, the Blue Witch at the East.
Rubi, the Red Witch at the West.
And Emeroud, th Green Witch of the far away North... a place called "the Great Nothing".
They're all a homage to Lyman Frank Baum's books of "The Wonderful Wizard of Oz".