The Romulans (Second Human Empire: Hamo Zuyy'yui Quikki'niu) were a humanoid race from the planet Romulus in the Alpha Quadrant. The Romulans were biological cousins of Vulcans, as they were descended from those who rejected Surak's reforms during the Time of Awakening in the Age of Elders era. The Romulan Star Empire was the Romulan state and one of the major powers known in the galaxy. Romulans joined the Axis of Empires to counter the Vulcans of the Alliance of Nations.
Due to their shared ancestry, Vulcans and Romulans possessed very similar physiology, including varied skin color. Romulans had pointed ears, eyebrows that were arched and up-swept, and copper-based blood that appeared green when oxygenated in the arteries, or copper or rust-colored when deoxygenated in the veins. Most Romulans had two brow ridges above the bridge of their nose, forming a V-shape on the forehead. However, a minority of Romulans lack these ridges, making them outwardly indistinguishable from Vulcans.