http://tappedout.net/mtg-decks/shhhhhhh-eoldred-the-reanimatrix/

Sheoldred, known as the Whispering One is the Praetor of the Black Faction of the Phyrexian Invasion on Mirrodin. Sheoldred speaks only in whispers. She is a small humanoid female attached to a large jaw which is used as a mount which she is capable of removing herself from. The black-aligned faction, led for the moment by Sheoldred, has one goal: enslave. Believers will serve. Unbelievers will be made to serve. All will bow to Phyrexia.

Besides her rank as a praetor, she is part of an unique rank in Phyrexianised Mirrodin, known as Thane. They appear to serve little more than as warlords of the Black faction, with no observable utility for the rest of Phyrexia and actually each thane intends to take over the plane. Using knowledge and secrecy to advance herself, Sheoldred intends to become omnipotent, but being in direct competition with equally ruthless thanes like Geth it is equally possible she fails.