Romulan Imperial Guard

The Romulan Imperial Guard was the military of the Romulan Star Empire in an alternate timeline where Humanity never evolved.

Several ships of the Imperial Guard encountered USS Enterprise (NCC-1701) and demanded the ship to surrender but were prevented from doing so by a Klingon Spear suicidal attack. Captain James T. Kirk remarked that he had never heard of the Romulan military referred to as the Imperial Guard. (TOS novel: First Frontier)