From Wikipedia of the Dark Jedi Brotherhood, an online Star Wars Club

In order to increase communication between the Assembly of Consuls and the Dark Council, the Grand Master has ordered that there be an Emissary (EMS) to the Dark Council. This person is chosen by the Consuls from among the Consuls to represent the Assembly of Consuls to the Dark Council. The Emissary serves as speaker to the Dark Council, but is in no way considered the head of the Assembly of Consuls. The Emissary simply serves to pass along ideas and suggestions to the Dark Council and Assembly of Consuls . There are no rank restrictions on the Emissary. The only necessity is that the Emissary is a fellow or former Consul.

The Emissary was created along with the Assembly of Consuls, which was instituted by Grand Master Chi-Long. This position has since been dissolved, Dark Side Adept Astronicus Aurelius Sadow was the last serving Emissary

The role of Emissary has been filled by: