Generals command the Tal Shiar. We estimate there are only around 10 Generals in the Tal Shiar, but that is unconfirmed.
A Note on Rank Insignia
All rank insignia is worn on the left uniform collar. In the field, Romulans often do not wear insignia, instead they work in small groups of <20 where everyone knows everyone else's rank. We believe this is done to confuse spying efforts.
Their are no Enlisted ranks in the Tal Shiar
General
Generals command the Tal Shiar. We estimate there are only around 10 Generals in the Tal Shiar, but that is unconfirmed.
Colonel
Colonels are the field commanders of the Tal Shiar. Colonels coordinate important, large-scale operations. They are almost always accompanied by up to 8 guards.
Major
Majors are the high-level operatives of the Tal Shiar. Majors are highly trained and valuable resources. They are not wasted on routine assasinations or intimidation, instead they act as deep-cover agents or supervise large-scale operations. They travel with 4-6 guards unless mission conditions prevent it. Tal Shiar officers of Major or above have the authority to commandeer any vessle of the Empire.
Captain
Captains are mid-level operatives of the Tal Shiar. Captains often act as Intelligence Officers in cooperation with the Romulan Fleet. They are sometimes also placed undercover in the Romulan Fleet or in regular society to spy on the public. They are sometimes accompanied by 2-4 guards.
Lieutenant
Lieutenants are low-level operatives of the Tal Shiar. Lieutenants occasionally are accompanied by 1 or 2 Guards. Lieutenants generally work on minor operations that do not warrant the involvement of more experienced, higher ranking officers.
Uhlan
Uhlans are the backbone of the Tal Shiar. They exist in the tens of thousands, and act as Guards for superior officers, or assassins, or general intimidation and espionage purposes.