Sith Order Levels

Initiate

Initiates posses only the most rudimentary Force powers.   They are under the formal, but sporadic, guidance of any higher level Sith.
Force Skills: 1D in any Force Skill Examples: Imperial Sovereign Protectors

Apprentice

An Initiate that proves himself worthy will be selected by an Adept or higher Sith to be his Apprentice.  The Apprentice will accompany his master on various assignments, but will rarely be sent out alone.  During the Apprenticeship, the Sith will hone their skills in preparation for the Trial.
Force Skills: 2D - 4D all skills (min - 6D total) Examples: Novar & Warb Null

Knight

A Sith, or Dark Jedi Knight, has completed the Trial and begins to work alone, although usually in the service of a Master.  Knights usually begin to focus their training to customize their skills for their particular interests.  They also are able to begin training Initiates, but few Knights find the time to do so.
Force Skills: 4D - 7D all skills (min - 12D total) Examples: King Ommin & Queen Amanoa

Adept

Adepts are extremely powerful Sith and posses many Force powers.  They are usually placed in charge of a Sith Sanctuary, which allows them access to ancient Sith writings.  There they study the Force while they protect the Sanctuary.
Force Skills: 7D - 10D all skills (min - 21D total) Examples: Gwellib Ap-Llewff & Savuud Thimram

Master

A Sith Master is at the pinnacle of his career.  Having mastered all aspects of the Force, a Sith Master begins to focus his abilities in the training of other Sith.
Force Skills: 11D - 14D all skills (min - 33D total) Examples: Darth Vader &Joruus C'baoth

Lord

A Lord is the highest level of the Sith.   Sith Lords are known to possess all powers and often have the ability to create new ones at will.  A Sith Lord can bend the Force to his whim, allowing virtually limitless power.
Force Skills: Above 14D in all skills Examples: Emperor Palpatine & Freedon Nadd