The Urbankans are a race of frog-like humanoids who secrete the deadliest poison in the known universe from a gland in their necks. They come from the slimy planet Urbanka, in the solar system of Inokshi, in the galaxy RA1489. They are a technologically-advanced race; their many developments include monopticons (floating-eye cameras with magnetic shields), a resonant stroboscope (for increasing density, thereby reducing matter), an interferometer and a graviton crystal detector (for measuring gravitation waves), a laser key and a directional cobalt flux (used for unlocking things), the science of telemicrographics (with which the Urbankans can effectively shapeshift) and advanced android technology.
Their supreme leader, named Monarch, seems to also be an accomplished scientist, and along with his ministers of Persuasion and Enlightenment, he has been making visits to Earth in his spaceship for 35,000 years. The Urbankans have no culture of their own which is comparable to Earth culture, so during each visit (which Monarch calls "dropping times"), the Urbankans rescued one member of an Earth civilization to travel with them - during the first visit, around 33,000 BC, they took an Australian aborigine named Kurkutji; during the second, around 6,000 BC, a Mayan princess named Villagra; during the third, around 2,000 BC, a Chinaman named Lin Futu; and during the fourth and most recent, around 500 BC, a Greek philosopher named Bigon. These four now act as the leaders for their respective groups of aborigines, Mayans, Chinese and Greeks aboard the ship. With continual modifications to his ship, Monarch has been able to approximately double his speed from Urbanka to Earth each time. 1,250 years ago, his ship left Urbanka for the last time; three billion Urbankans escaped the planet just before their sun collapsed and created a black hole. Now they wish to resettle on Earth.
But what Monarch does not like to share is that Urbanka was not destroyed by its sun; in fact, Monarch's experimentation exhausted Urbanka of its minerals, his technology polluted it and destroyed the ozone layer, and as a result Urbanka was scorched with UV light. Monarch was able to overcome what he called the "Flesh Time" - the mortal coil, basically - by creating advanced androids with chips for memory, reasoning and intelligence, and motor functions. Mortal beings are put into a device which puts them into a trance and causes them to recall their entire lives; this information is then put onto the chips, which are transferred to the androids, and the original organic body is then destroyed and used to fertilize the Urbankans' floral chamber. Monarch had originally taken several humanoids from each period of Earth's history he visited; but only the greatest intelligences were allowed to survive, and the others were buried in the floral chamber. Presumably these people were turned into the slave androids that Monarch keeps, with only one chip (motor skills) out of three and metal implants on their hands, directed by the leader of their respective ethnic group. Revolt against Monarch is strictly forbidden, and any attempts to do so are punished by 100 years of being put in the repository of personality chips.
Monarch has told his four Earth representatives that he wants to save the population of Earth from the Flesh Time, and that once everyone has been liberated from their mortal existence, he will give Kurkutji, Villagra, Futu and Bigon dominion over their respective cultures. But what he really wants is the silicon that is so plentiful in Earth's crust, and useful for creating more chips for his androids. Monarch has been cultivating the Urbankan toxin in frogs from Earth; one-trillionth of a gram of it will cause a person to shrink to the size of a grain of salt. With this, he plans to replace the population of Earth with the three billion Urbankans he has stored on chips in the ship. Having persuaded Adric that he is a wise and peaceful man, he hopes that Adric will in turn persuade Earth that he has their best interests at heart.
Once this is accomplished, Monarch will work toward his ultimate goal: to travel faster than the speed of light. He believes that if he can accomplish this, he will travel back in time to the Big Bang, where he will meet himself...for Monarch believes that he is God.
The Doctor and Adric are able to take care of Persuasion and Enlightenment by removing the connections to their chips; and Monarch is destroyed when the Doctor throws a vial of the Urbankan poison at him. Monarch is shrunk to an infinitesimally-small size, proving that, despite his zealous advocation of giving up the Flesh Time, even he had not completely abandoned organic living.
