Remus

Remus is the tidally-locked, Q-class sister world of Romulus, and the homeworld of the Reman species with both being located in the Romii system (TOS novel: Captain's Blood)

It is also known as ch'Havran (in Rihannsu) and 128 Trianguli III-B (in Earth's astronomical notation); the planet is a major source of dilithium, and it is often used by the Romulan Star Empire as a place of punishment to which political prisioners are sent for slave labour. (Star Trek Nemesis)

The dark side of the world is a cold wasteland with pockets of ice made of frozen gases. The ores that were present on Remus include; Duranium, Pergium, Uridium and Zenite. The varying degrees of radiation also suggested the possibility of thalaron radiation being generated within certain regions of the surface making such locations dangerous. Its designation is a Quaris class world. (novel: Vulcan's Soul: Exiles)

The planet would be defended by at least three warbirds of unknown class which were crewed completely by Remans. In order to ensure that the Remans did not rebel with such powerful 'assets'; the ships only had a maximum warp factor of three. In addition to this, each ship was linked to a Reman commune on the planet itself. Should any of these ships rebel against their Romulan masters, the commune would suffer. (TOS novel: Captain's Blood)

History
Historians believe that Romulus and its sister world of Remus were in fact once a single large planetoid known as Romii. The biggest change that geologists have determined to have to Romii was five-point three billion years ago when another planetary body, which was at least sixty percent the size of Romii and in retrograde orbit, collided with the large planet. The impact stripped the outer crust from Romii and, in less then two hundred years, the ejecta had coalesced into a single body that would eventually cool to become the planet known as Romulus which would continue to spin with the force of that ancient catastrophic collision.

The other half of Romii, which was composed of primarily heavy core elements, became Remus which had been superheated by the impact and the concurrent energy release of its axial revolution being stopped dead. After two million years of erratic oscillations before stable orbital resonance was achieved. The world would be known as perhaps the richest planet in both the Alpha and Beta quadrant in terms of exotic mineral wealth. This came at the price of the world being virtually uninhabitable because it was gravitationally locked to its sun so that one day equaled one year, keeping the same face in constant sunlight and the opposite in perpetual night.

The planet was known to have unusually heavy gravity for its size, one point five standard G's for a world barely the size of the planet Mars, with complex chemistry producing an atmosphere of sorts. (TOS novel: Captain's Blood)

Pocket Books continuity
Remus, and its sister world of Romulus, were both named after an ancient Vulcan myth of twin god-brothers that were different but always united.

Despite the harsh conditions of the planets surface, there were evidence of life when the ancient Romulans first surveyed the planet. The initial expedition noted at least thirty six different kinds of extremophiles which were located by the volcanic vents beneath the ice. (novel: Vulcans Soul: Exiles)

Rihannsu continuity
Alternately, ch'Havran is an M-class world, slightly smaller than its twin. "Frozen" in orbit around ch'Rihan, the planet has five mountainous and heavily forested continents, with thousands of species of wildlife, many of which are shared with its sister world. The planet also has rich deposits of dilithium.

After the Travlers made planetfall, they held a lottery to allocate living space and resources on the Two Worlds. Whether by accident or sabotage, many of the "reactionary," Vulcan-oriented clans "won" land on ch'Havran. Alongside them were almost all of the "troublesome" groups from the journey, those that had been pressured into the exile by one faction or another; most of these groups wound up on the eastern continent, harsher and poorer in resources than the others. Cut off from both ch'Rihan and the rest of ch'Havran, the eastern continent-dwellers developed as cruel and savage, even by Romulan standards. Two of the nation-states that developed there were the Kihai and the LLunih. In the 22nd century, the eastern Havranssu were responsible for instigating the Earth-Romulan War, and in 23rd century, the abandonment and "evacuation" of the Thieurrull colony, and the capture and rape of innocent Vulcans.

In the centuries to come, the Havranssu came to be known as the "dissenters" of the Empire, and by the 23rd century, were subject to several Imperial "crackdowns," resulting in the ill-will that eventually contributed to the Romulan Civil War of 2276.

Some fifty years after settlement, a mutated lunglock virus spread to the planet from ch'Havran, reducing the combined population of the Two Worlds to around nine-thousand. Only "forced" multiple-births, creche techniques and limited cloning enabled the Rihannsu to survive. Eighteen years later, a famine struck the southern continent, and nearly half its population died of starvation. 

Way of D'era continuity
Remus, or Ket-cheleb IV, is an M-class world, smaller than Romulus, having a diameter of 11,450 kilometers at the equator, and a somewhat cooler climate. The planet has four continents, Astrakoth, Goreb, Kel'var and Valis'Shar, and a large chain of islands, the Zandranek Archipelago.Its capital city is Jaralex'Vanar.

Though not suited for agricultural pursuits, the planet possesses extensive natural resources, and by the 24th century was almost completely given over to the Romulan Star Empire's military industry. For this reason, Remus is off-limits to non-Romulans, except for the native, and conquered, Zelvorians (who called the planet Romii). (Last Unicorn Games RPG: The Way of D'era: The Romulans)

Cities and Settlements
While the Federation knows very little about Remus, long-range sensors have been able to make a rough map of the Remus settlements. There are 7 Romulan military colonies spread out on the dark side, and several dilithium mines surrounding them. The mines spread kilometers into the surface of the world.

Fauna

 * Trelka
 * Vas'deletham