Sith Warlord, Obelisk Primarch, or Krath Pontifex (commonly known as Equite 4 or EQ4) is the twelfth rank in the Dark Brotherhood, which is awarded after demonstrating above and beyond performance as a 3rd level Equite. It is at this rank that members may request custom Dual Lightsabers.
It is the final rank in the Equite class, the last step down the path to Dark Side Adept.
Promotion past this rank is determined by your Clan Summit when a promotion is warranted based on performance and activity.
Upon promotion by your Clan Summit, you will reach the first Elder class rank of Dark Side Adept.
Trivia
For a while between 2003 and 2005, Sith Warlord was at Equite 3, on a par with Obelisk Exarch and Krath Epis.