|Affiliation:||Romulan Star Empire|
Remus was an inhabited planet. This was the homeworld of the Remans, a humanoid species enslaved by the Romulans. It was the third planet in the Romulan planetary system. This system was located in Sector Z-6, which was a region of space in the Alpha Quadrant. The planet was affiliated with the Romulan Star Empire.
The location of Remus in the Milky Way Galaxy was depicted on a Federation star chart in 2293. (TOS: "Balance of Terror", display graphic; DS9: "The Search, Part II"; Star Trek VI: The Undiscovered Country, production art; Star Trek Nemesis)
After Romulus was settled by a group of Vulcan dissenters over a millennium ago, the settlers turned their attention to the inhabited Remus. They conquered this unforgiving world and enslaved the indigenous population. The slaves were put to work as miners and the exploitation of Remus for its rich dilithium sources began. Over time, the Romulans put the slaves to work building heavy weapons. The Remans were regarded as an undesired caste in Romulan society.
Remus and Romulus were the major worlds of the Romulan Star Empire, one of the great powers in the Alpha Quadrant. However, Remus and its inhabitants had been excluded from Romulan politics until 2379, when Shinzon, a Human clone imprisoned on Remus, became Praetor of the Romulan Star Empire by a coup d'état. However, his plans to annihilate Earth and to crush the Romulan government were thwarted by the Starfleet Captain Jean-Luc Picard.
In Roman mythology, Romulus and his brother Remus were known as the brothers who founded the city of Rome. Romulus became the first king after killing his brother. The relation between the planets of Romulus and Remus reflect this. See Romulus and Remus. This would indicate that Romulus and Remus, along with Romulan, Reman, were names drawn from Earth mythology, not their own terms, which makes sense because the Romulan/Reman languages are different. There is ample precedent, as many peoples on Earth call themselves by different names than those which others use for them.
In "The Aenar", the two Romulan drone-ships are seen departing a planetary body without an atmosphere with Romulus being visible in the background. It remains unclear whether the scene was supposed to show Remus or merely another asteroid or moon.
"The Explored Galaxy"
"The Explored Galaxy" was a map of charted space in the Alpha Quadrant. The chart was also seen in several Star Trek: The Next Generation and Star Trek: Deep Space Nine episodes set in the 24th century, from the year 2364 to 2370. These were TNG: "Conspiracy", "The Measure Of A Man", "The Emissary", "The Mind's Eye", "The Game", and DS9: "In the Hands of the Prophets", "Cardassians".
Remus was a Q-class planet. The official name of the uniglobal government was the Reman Colonies. The dominant species were the humanoid Romulans and Remans. Remus was in or near the Romulan War Theater of Operations (2156-60). (pgs. 55, 66)
In some non-canon Star Trek novels, Romulus was called ch'Rihan and Remus was ch'Havran. The Romulans are the Rihannsu, and Remus was said to be the more temperate of the two planets.