Reman

Romulus apparently had no sapient species until a proto-Vulcan splinter group colonized it around 400 CE. These proto-Vulcans over time became the Romulans. A native sapient species called the Remans developed on Remus and was conquered by the Romulans later becoming a lower class in Romulan society.

The original colonization group of Vulcans came to this system after they fled their homeworld in rebellion against the philosophy of peace and logic proposed by Surak. As Mr. Spock would later point out, if the Romulans retained the passions and expansionist outlook that the pre-Surak Vulcans once had, it would make them an extremely dangerous race.... the Remans who were subjugated ever since the Romulans staked claim and set up their new homeworld in the system. Because the planet is tidally locked to its sun and the species, which lives on the cooler night side, is in constant darkness, the Remans are extremely sensitive to light.

The Remans were treated as second class citizens within the Romulan Star Empire. Remus is the prime planet of dilithium mining and as such many Remans are forced into slave labor.

Much about Remus remains a mystery, but hopes of a more co-operative future between The United Federation of Planets and the Romulan Star Empire have been strengthened since Shinzon's fall.