Sulken, Stronghold of Darth Fell, Lord Apprentice

"Without power, wisdom decays."

All Sith Houses have a common structure. At the top is the Dark Lord, the unquestioned dictator. He takes the title Darth followed by the name of the House (so House Archanis is ruled by Darth Archanis). The Dark Lord has sole possession of the most secret lore of the House, which serves as insurance against assassination.

Under the Dark Lord is the Lord Apprentice, his student and named successor. By tradition the Lord Apprentice takes the title Darth as well, followed by a name of his master's choosing. When he ascends to the throne he changes his name to that of the House (though on rare occasions he might rename the House to match his own). The Lord Apprentice is almost always the second most powerful Sith Master in the House.

Next in importance are the lesser Sith Lords. When a Sith reaches the rank of Master, he is given rule over his own domain. Often this is an inhabited star system, though it can be multiple systems or part of one rich or densely-populated system. These Sith Lords comprise the Court of the Dark Lord, a body ruled by ambition and intrigue.

Serving the lords are the Sith Knights. These powerful warriors and sorcerers take roles in a lord's court according to their own specialties generals, chancellors, enforcers, spies, assassins, etc. In turn a Sith Knight may choose an apprentice from among the initiates who survive their childhood training. In all a large House may count more than a hundred Sith among its number.

Apprentice is the lowest rank among the Sith. All other beings in the galaxy are chattel.