Dalek

The Daleks are the major antagonists of the Doctor Who universe, who are a breed of genetically altered Kaleds from the planet Skaro. The Daleks were created by a megolomanial Kaled war scientist called Davros under orders from the Kaled high council. The project was designed to build a weapon capable of defeating the Kaleds ancient enemy, the Thals; Davros betrayed the Kaled council and instead designed his own supreme being, capable of surviving the nuclear wasteland that Skaro had become. Davros removed from his creation all emotions other than hatred and contempt. The Dalek alien is a genius programmed from birth to regard all other species as inferior, a lack of foresight on the part of their creator as the Daleks eventually killed him (although he returned from death later on.) Before their fall at the hands of the Time Lords the Dalek race split into two factions, the renegade Daleks, under the command of the Supreme Dalek, and the Imperial Daleks, under the command of the Dalek emperor (the resurrected Davros.)

Shell Description
Daleks have a very durable shell, made from 'dalekanium', a fictional element. They have a rotateable mid-section, (usually) bearing the gunstick and a plunger-like manipulator of great power. The head dome is also fully moveable, and the eyestalk can move up and down. This eye provides wide-angle vision, with zoom and presumeably accuracy assistance. The Dalek's eyepiece was its most vulnerable spot, and impairing its vision often led to its main weapon being fired indiscriminately. The Dalek casing also functioned as a fully-sealed environment suit, allowing travel through the vacuum of space or underwater without the need for additional life-support equipment.

The Dalek has many domes around its lower shell, acting as sensory substitutes, explosives, and supposedly also having other such functions. Within this, the Dalek creature is housed, surrounded by screens and machines, and attached to the life-support system.

Daleks have force fields that make them very difficult to kill, melting incoming bullets. They also have very powerful weaponry, most famously the 'gunstick', with various levels of power ranging from 'stun' to a level which can destroy a large house. Famously they cannot climb stairs, but they can hover (or, as they put it, elevate) to solve this problem. Daleks also have the ability to time travel, both using their own time machine and by performing a temporal shift (this ability may be limited to the Cult of Skaro). At the height of their power, 4 Daleks could conquer the World (this may have been a taunt).

The voice of a Dalek was electronic, the Dalek creature having no vocal apparatus as such. Their most infamous statement was "EX-TER-MIN-ATE!", with each syllable individually screeched in a frantic electronic scream. Other common utterances included "I (or WE) OBEY!" to any command given by a superior. Daleks also had a radio communicator built into their shells, and emitted an alarm to summon other nearby Daleks if the casing was opened from outside.

Dalek Creature Description
The dalek creature is pallid, with many tentacles and the remnants of eyes and a mouth. It has a large brain which shows through its skin, and supposedly has a very high processing ability and intelligence level. It is almost helpless without its shell, though it could kill using its appendages.

Psychology
Ultimately, the most fundamental feature of Dalek culture and psychology was an unquestioned belief in the superiority of the Daleks. Other species were either to be exterminated immediately, or enslaved and then exterminated later once they were no longer necessary. They shout 'Ex-ter-min-ate!' before fighting and/or killing; they rarely use the word 'kill', preferring 'exterminate'. Talking about their execution of the Master, an evil Time Lord, he says that he was 'exterminated' by the Daleks, and Captain Jack refers to 'death by extermination'. Another offshoot of this superiority complex was their complete ruthlessness, although this is also due to genetic modifications made to the original Kaled mutants by Davros. It was because of this that it was nearly impossible to negotiate or reason with a Dalek and it was this single-mindedness that made them so dangerous and not to be underestimated. However, their reliance on logic and machinery was also a weakness, albeit one that they recognized in themselves.

Daleks had little to no individual personality and a strict hierarchy. They were conditioned to obey a superior's orders without question. Due to their frequent defeats by the Doctor, he became a legendary figure in Dalek culture and mythology. They had standing orders to capture or exterminate the Doctor on sight, and were occasionally able to identify him despite his regenerations. This was not an innate ability, but probably the result of good record keeping. The Daleks knew the Doctor as the "Ka Faraq Gatri", (which meant the "Bringer of Darkness" or "Destroyer of Worlds"), or as the "Oncoming Storm".

History:
Note spoilers

The Daleks opposed the Time Lords in the Last Great Time War. Many worlds were destroyed in this war, fought in the Eternal Void and the Time Vortex itself, including Skaro. Massive fleets clashed, and both species were nearly wiped out. Near the end, nightmarish creatures and entities began to form under the strain of the subtly warping universe, and the Doctor resorted to The Moment, which destroyed all parties involved in the Time War and locked it against time travel.

The Doctor thought he was the only survivor, until he came across a Dalek that had been captured and tortured by Humans. This Dalek absorbed Rose Tyler's DNA to rebuild itself, but gained her emotions so destroyed itself.

The Dalek Emperor also survived and created an army of Daleks from the bodies of dead humans. These Daleks hated their own existence because they had begun life as an inferior species. On the verge of conquering Earth, they were destroyed by Rose Tyler, the Doctor's human companion, who had absorbed the power of the TARDIS to save the doctor.

However, the Cult of Skaro, 4 Daleks whose purpose was to imagine and think like their enemy (regular Daleks have no imagination), survived by hiding in the Void. They hid with the Genesis Ark, a Time Lord prison ship which held millions of Daleks, and entered the world after the cybermen opened the Rift to the Void, allowing the Cybermen army through. There was a great battle, with the Daleks clearly winning, but the Doctor reopened the Void and all the Genesis Ark-held daleks and cybermen were sucked in. The Cult of Skaro escaped through the use of an 'Emergency Temporal Shift'.

Their leader, Dalek Sek, was imprisoned by the other 3 when, after turning himself into a Human-Dalek hybrid, he said that Daleks were not supreme and planned to continue the species by creating hybrids using the bodies of humans whose minds had been destroyed. He was later accidentally exterminated when he tried to save the Doctor, who Dalek Sec claimed was the key to saving the Daleks. His experiment was interrupted by the remaining members (breaking the law that 'Daleks must obey'), and the results were humans with the minds of Daleks. However the Doctor got in the way of the gamma beam, mixing in Time Lord DNA, so the Dalek Humans had curiosity and some free will, and destroyed 2 more members of the Cult of Skaro. The final member, Dalek Caan, escaped from the Doctor (who was offering to help him) using an emergency temporal shift, and the Doctor said that they would meet again.

Before they did, Caan had travelled to and from the Time War and brought back Davros, the original creator of the Daleks. Caan's entering the War meant he absorbed the knowledge of the universe, and realised the Daleks had to be undone. Davros created an army of real, true Daleks and created a 'Reality Bomb', a matter-annihilating device, amplified by being broadcast through certain planets, of which Earth was one. The Doctor, aided by a Metacrisis-produced human Doctor and a Donna with a Time Lord mind, eventually destroyed the entire army and left Davros in an exploding ship.