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"For all the discomfort and fatigue, and fears as to what might happen, the first impulse I had was to laugh. They were so grotesque!"
Will, The City of Gold and Lead

Master full.jpg



The Masters are an alien species from Trion that invaded Earth and enslaved almost the entire human population with Caps. They are the manufacturers of the Tripods and the main antagonists of The Tripods franchise.


The Masters originally evolved on a hot and humid planet called Trion. Nothing else is known about their past before their arrival to Earth, except that they had been exploring space and colonizing other planets before.

The Masters found and came to Earth in the mid 1980s. Observing that the human species would be a formidable foe in battle, the Masters decided to study them before revealing their existence. At some point they landed three of their automated Tripod vehicles on Earth: One in Great Britain, one in the Soviet Union and one in the United States of America. While the Americans waited and watched, the Soviets destroyed their Tripod instantly. The British tried a friendly approach with classical music, but when the Tripod destroyed a house and kidnapped one of the humans inside, they sent tanks and planes to destroy it.

Due to the apparently short-lived invasion, people initially ridiculed the Tripod invasion, believing that the aliens had been easily destroyed. But the Masters had realized that they could not win against humans in open combat, and turned to another method. They utilized television technology to create a program called The Trippy Show, which hypnotized many of those who watched it.

At first, the 'Trippies' were a nuisance more than anything, but over a couple of weeks, their numbers grew and they began causing problems in cities and leaving home to join communities. A second wave of Tripods landed, and the Masters gave their followers mind control caps made of metal and rubber. They were first given to those who were willing, and then put on others by force.

A civil war began, fought between the Capped and the free people. However, as more and more people were capped, there were fewer free people to fight. Eventually, the removable caps were replaced with wire caps embedded into each human's skull. The resistance dwindled to a few small pockets, and though free humans survived for several months in submarines, even they were eventually hunted down.

After a hundred years had passed, few even remembered where the Tripods had come from. Large cities were abandoned and humans returned to a medieval-like agricultural life. The Masters ruled from three domed cities they built. Every human was Capped at age 14 and contests were held to choose the strongest boys to serve the Masters in their cities. A constant supply of new slaves was needed because the harsh conditions of the cities quickly wore out the humans who were brought there.

The Masters were defeated after a resistance group sent spies into the cities and learned that the Masters' ultimate goal was to transform Earth into a place they could live, killing all Earth life in the process. After a Master named Ruki was captured, it was discovered that the Masters could be overpowered and paralyzed by putting alcohol into the water supply. Three teams set off, and two of the attacks succeeded. Once the cities were powered down, the caps of those inside no longer worked, and the humans could be helped to escape.

The third attack failed, and an alternate plan had to be formulated. A bombing raid was carried out. Primitive airplanes were first used, but the Masters saw the attack coming and used an electromagnetic pulse to shut down the engines and crash the planes. A second attempt was made soon after with hot-air balloons, and it too appeared to be failing, as the bombs bounced off and detonated too high to damage the city's dome. However, one of the protagonists plants his bomb, sacrificing himself but accomplishing the goal of destroying the city.

As humans began to rebuild their civilization, the alien mothership approached Earth. It was feared that they might bomb Earth, but they struck only their three destroyed cities, obliterating them and the humans studying the technology inside to prevent reverse engineering of their technology.


Artist Wayne Barlowe's impression on the Masters based on the books. (From Barlowe's Guide to Extraterrestrials)

According to a description in The City of Gold and Lead, the Masters were much taller than a man, nearly twice as tall, and broad in proportion. Their bodies were wider at the bottom than the top, around four or five feet, but tapered up to something like a foot in circumference at the head. They do not have necks. A notable feature of the Masters is that they have three thick and short legs. They have also three tentacles as arms, issuing from a point halfway up their bodies, as well as three eyes. One eye is above and between the other two.

The color of the Masters is green, though the shades differ from dark and brown to pallid. There is also known height variance between individuals. The Masters have a separate mouth and breathing hole, making it look like they have two mouths, but in fact the upper one is merely for breathing.

The Masters breathe a thick and green air, like a chlorine fog. The composition of the air is never revealed in the books or TV series, however. The air of the Masters has a hazardous effect on human health, just like human air has for the Masters.

Food eaten by Masters is very different from that eaten by humans, although the exact differences are unclear. Masters have the ability to somehow sense harmful additions to their food, and will simply refuse to eat anything that contains drugs or poisons, with the exception of ethyl alcohol, to which the Masters have a very low tolerance.

The Masters prefer high temperatures. Room temperature for them is somewhere around 40 degrees Celsius. The pools that they bathe in are often extremely hot. This indicates that their digestive and respiratory enzymes are quite different from those found in terrestrial life.

A Master's preferred method of moving, described as a slapping hop on all three feet, is light and fast, completely untroubled by the incredible weight that their size must hold. As shown by this lightness in a heavy environment the Masters are, physically, extremely strong, able to easily lift a human with just one of their three tentacles. Their skin is described as being damp, reptilian and leathery and is therefore very resilient to attack.

The Masters do have one crippling physical weakness. The area between their respiratory orifice and their ingestive orifice is extremely sensitive. A light brush to this area causes extreme pain. More forceful contact causes unconsciousness or death.

The Masters are vulnerable to at least one kind of illness. In The City of Gold and Lead it is called "The Curse of the Skloodzi". The disease evidently causes sufficient discomfort as to preclude work. Gas bubbles and bathing are known to ameliorate discomfort. The ailment also causes the skin to discolor somewhat, becoming streaked with brown.


West 468, Will's Master.

The Masters are completely incapable of lying, finding it difficult to tell the difference between a novel and a biography. As such they are extremely gullible, taking everything told to them as indisputable truth.

Their reaction to despair is a unique one. The Masters are incredibly tolerant of hardship and difficulty, to the point of becoming ill if they do not work hard. However, if they find themselves in a situation to which there is absolutely no escape, they die. It is unknown whether this is natural or some form of suicide. When the Masters' xenoforming ship turned back after discovering the success of the human rebellion, the last Master on Earth, a prisoner of the Freemen, died. It is not explained how it knew that it had been abandoned.

Masters have very little in the way of a social life. They spend most of their time in their own home. It is unlikely that Masters form any kind of nuclear family; throughout the books there is no mention of there being any more than one Master to an apartment. On the rare occasions that they do meet with others, very little conversation or activity between the two takes place. There are various events and functions around their city - communal baths, museums, and others that have no human equivalent - but each Master will attend and enjoy these events on their own. Even when in close proximity to other Masters doing the same thing, they are unlikely to engage in any kind of social intercourse, and if they do then it will be short-lived and limited.

Several forms of recreation existed. One, the Sphere Chase, involved Masters in smaller versions of their Tripod vehicles chasing a glowing sphere, with the evident goal of directing it through an opening in the side of the arena. Others involved listening to strange (by human standards) sounds or watching strange lights.

Masters seem to appreciate alien beauty. They accepted men and women into their cities, but only men served as slaves. They killed and preserved the women, arranging them according to aesthetics of their own devising. In one exhibit, Will finds a woman he loved arranged with other red-haired women in the order of shades from darker red to lighter red.

But this, and their habit of taking slaves generally, suggests that they do not hold life other than their own in high regard. Although some provision was made for slaves exhausted by heavy gravity to recover, slaves who became convinced they would not recover were programmed via their Caps to go to The Place of Happy Release. There, some form of energy killed them, and a moving belt carried the body to a furnace for incineration. The most profound indicator was their long term plan for Earth: en route from their home at the time of "The City of Gold and Lead" were spaceships containing components they could not manufacture on Earth, parts of great machines that would accept Earth's atmosphere and turn out an atmosphere like that found on the Masters' home and in their cities. Such a transformation would be eventually fatal to all life on Earth, except such few live specimens that the Masters were debating whether to house in zoos.

At least some Masters enjoy an intoxicant they call a gas bubble. The master places the plastic bubble near his respiratory orifice and breaks it, then inhaling the vapor. The effect is evidently mild; it takes several such bubbles to create personality changes noticeable to humans. Use of gas bubbles brought out latent personality traits in at least one Master.

The Masters are not of uniform character. Will's Master is somewhat of an intellectual, constantly questioning and studying and learning. His reading of human literature awakened a loneliness, so he wishes to keep Will as a beloved pet. Fritz's Master, however, is a sadist, most interested in physical exertion as well as inflicting pain on whatever slave he happens to have at the moment. The captured prisoner, Ruki, the only Master to be named in the trilogy, is explored little. However, he is the only Master seen to display any understanding of humor and sarcasm.


The Masters power their city with a form of atomic energy that appeared to uneducated and casual observers as a "pool of fire." This description lent itself to the title of the third novel. It is loosely inferred by Beanpole to be nuclear fusion. A concentric series of chambers located near the center of the city and below ground level housed this apparatus; the various doors did not align, so that it was necessary to travel around the perimeter of each chamber to the next entrance. Within the innermost chamber was a single lever that functioned as a main breaker. Moving it from the operating position to the off position deactivated the mechanism, while moving it in the other direction reactivated it. Contact with this lever while the mechanism operated proved instantly fatal to humans.

The most visible artifacts of the Masters were the Tripods; immense machines that walked the world outside their cities on three long legs. Described as hemispherical, with legs equidistant, the tripods could interact with the world using long, tentacle-like manipulators, each of which was capable of lifting and crushing a Challenger 1 tank. At least some of these machines had chambers suited to Earth life, and could take individuals inside them for extended periods. When they reached age fourteen, individuals were taken inside a Tripod to be Capped: the machines visited larger towns, while individuals from smaller towns traveled to a nearby larger town to be Capped. Tripods seemed to follow a route consistently but whether this was due to the psychology of their pilots or to some form of autopilot was never revealed. Among the facts inadvertently revealed to Will by his Master was the crew size: four individuals.

Much of the Masters' industry appeared highly automated. Machines operating without supervision created everything from food and air to intoxicants. Among these were machines that created gravity at levels roughly twice that of Earth. According to Will's Master this is less than the gravity enjoyed by the Masters on their home planet; it is not revealed if this is due to technical restrictions, energy saving or because such extreme gravity would be very wearing on their human slaves.

The Masters' technology included precision machining techniques. Their airlock doors fitted so precisely that the seams were nearly invisible, and did not require gaskets or other flexible seals to compensate for imperfections.

They had the means to remove heat from objects, akin to air conditioning. Because of their water requirements, each of their cities straddled a major river. As part of treating the water before it left the city, mechanisms cooled and filtered it until it was very close to its original outside characteristics of temperature and composition.

Perhaps their greatest technological skill was in the area of mind control. They understood brain physiology to a high degree. In When the Tripods Came they captured at least one human for the purpose of dissection; the individual's corpse was discovered later, his brain neatly drained and removed. They later intercepted broadcast television signals, and added their own additional signals to the feed; these signals contained hypnotic suggestions. While not universally effective, these suggestions affected sufficient numbers of people so that the Masters had a substantial base of support in their early invasion effort. Whatever the method, these signals could convey detailed technical data and some of the individuals under this control constructed and distributed the first Caps.

Although their televised hypnosis was not permanent, control through a Cap evidently was, for as long as the Cap remained in place. Caps contained a fine mesh somewhat resembling an antenna. The first versions resembled ordinary hats and could even be removed, although the individual wearing such a cap would never voluntarily remove it and would actively attempt to prevent others from doing so. Successful removal of a Cap sometimes caused the individual to react in bizarre ways, becoming irrational or breaking down in tears. In a later phase of the invasion, Tripods dispatched to various locations removed the temporary caps and replaced them with Caps "married to the flesh" through some kind of bioengineering. These Caps could not be removed, although White Mountains resistance fighters eventually learned how to disable them by severing certain of the metal filaments. The Caps evidently depended on some form of transmission from within the cities of the Masters - when resistance elements turned off the city power supplies, Capped individuals ceased to venerate and obey the masters. As earlier, some reacted irrationally to the loss of outside will, even to the point of suicide.

Caps created a worshipful attitude toward the Masters; an unhesitating obedience so profound that the Masters did not fear bringing Capped humans into their cities. According to "The White Mountains," about one person in twenty became a Vagrant due to some failure of the process. Will speculated that the Vagrant's brain attempted to resist the power of the Cap and eventually broke under the strain, usually if a mind was too weak and collapsed or if a mind was too strong and collapsed resisting the cap. Vagrants were considered harmless (although this was not always true), but were generally unable to remain in one place for any length of time. Each community considered it a social responsibility to care for these unfortunates, who were unable to work, form families, or participate in most of society. Individuals seeking the resistance in the White Mountains were cautioned that if caught and Capped in a place where the natives spoke a different language, Vagrancy was almost certain, suggesting that each Cap received and relayed signals specific to expected thought processes of the wearer.

The Masters had a means of suppressing electrical activity at range. They disabled a biplane attack on their Central American city in this fashion.

TV Adaptation[]

The Master responsible for the Power Elite in the TV series.

When the BBC made the television series of The Tripods in the '80s they departed from Christopher's description. The Masters somewhat resembled the Tripods they drove. This makes the Tripods themselves seem much more like mecha than purely eccentric vehicles. In the series, the Masters did not need to eat, sleep or drink. Additionally, they were not the rulers of the city, but were themselves under the rule of beings made of pure energy, known as Cognoscs. The Masters themselves came from a planet named Trion that was in the center of a triple star system.

The method by which the Masters name themselves is also different. Rather than having names they are simply called by their address. Will's Master is called West Avenue 4, Sector 6, Level 8, or West 468.

The Masters in the BBC production did not prefer the high gravity and high temperature of those in the book, since these would have been extremely difficult or expensive to recreate onscreen at the time. Their treatment of the slaves, rather than being harsh and thoughtless, was reasonable to the point of being friendly; with luxuries provided for them.

Known individuals[]



TV Series[]

  • City of Gold
  • Will Is Made a Slave
  • Hunt for Eloise
  • The City of Gold
  • Blessings of the Cognosc
  • The Cognosc Departs
  • Escape From the City of Gold (Mentioned only)