The armed forces of the Romulan Star Empire, a fleet of cloaked warbirds commanded by ambitious officers and watched at every turn by the Senate and the secret police of the Tal Shiar.
The Romulan military first appears in the Original Series episode Balance of Terror, in which a single bird-of-prey with a cloaking device and a plasma weapon tests the Federation's border defences. The Enterprise Incident shows its officers flying ships of Klingon design.
In The Next Generation the fleet returns in The Neutral Zone with the huge D'deridex-class warbird. Commanders such as Tomalak and Sela pursue schemes including the planned invasion of Vulcan in Unification, while Face of the Enemy and The Defector reveal the mistrust between serving officers and the Tal Shiar.
The military joins the war against the Dominion in the Deep Space Nine episode In the Pale Moonlight. In Star Trek Nemesis a faction of its officers led by Commander Suran backs Shinzon's coup, before Commander Donatra turns her warbirds against him.