Darth Vyrassu
Immortal Jen'ari Sith Emperor
The Rule of One was the name of a Sith doctrine developed by Darth Krayt and followed by the One Sith. Darth Krayt's doctrine, as followed by the One Sith focused, in stark contrast to the core tenets of the old Sith, on obedience rather than conflict and survival of the strongest, with many Sith following one leader and purpose