As its colloquial title implied, the borders of Varuz were marked by an extensive mountain range on one side and a vast sea on the other. Much of Varuz consisted of a great, sloping valley that lead down from the mountains to the sea, criss-crossed with rivers and streams. The northern areas of the country were described as "rough and wild", whilst the southern areas were used as farmlands.
At the heart of the country was its capital city, a great stronghold built around one of the larger rivers. Most of the activity in Varuz was concentrated in the capital; aside from the city, only a few other small settlements existed. (PROSE: Royal Blood)
At one point in time, Varuz was an influential and technologically advanced civilisation, which held great power over the other nations of its world. The technology of Varuz, which included spacecraft, teleportation equipment and laser swords, was powered by drawing energy from the earth itself; eventually, the overuse of such technology started to wreak havoc with the natural landscape of the country, leading to the nation's decline, and they lost much of their power and influence. After hundreds of years, the people of Varuz no longer understood how their old technology worked, nor why the country was slowly falling into ruin.
By the time of the Twelfth Doctor and Clara Oswald's arrival, Varuz was under the leadership of Duke Aurelian, and was in a severe state of disrepair. Despite the protests from his advisors and friends, Aurelian insisted on going to war against Conrad, the ruler of a neighbouring nation, in a desperate attempt to salvage some of the old power and influence of Varuz.
After Aurelian was killed by Mikhail in the war, and Varuz was subsequently captured by Conrad's forces, much of the old technology of Varuz was destroyed. The Doctor informed Lord Bernhardt and Duchess Guena of the dangers of using such technology as they fled the capital city during Conrad's invasion, having realised too late the true nature of the ancient technology of Varuz.
By the time Bernhardt had reached old age, Varuz was all but forgotten; as he put it, "Varuz is lost now. Even the name has gone. The maps have been overwritten; the books burned or locked away in some forgotten library; the children taught different stories in a different tongue." (PROSE: Royal Blood)