The Daleks are a fictional extraterrestrial race from the British science fiction television series Doctor Who. They originated from a humanoid race known as the Kaleds, which suffered prolonged exposure to radiation following a thousand-year war with their neighbours the Thals, devastating their homeworld of Skaro. Many Kaleds began mutating due to this exposure, and the Kaled scientist Davros experimented with the mutants and determined the final form they would eventually take. The end result was a highly intelligent yet diminutive and grotesque creature, incapable of surviving on its own. Davros then built special machines for the mutants: armoured robotic shells that would sustain the mutants and allow them to travel. And thus, the Daleks were born.
The Daleks are cold, ruthless beings that have had their emotions removed, save one: hatred. They are completely xenophobic, believing that they are the superior beings and that all other life-forms are inherently wrong and undeserving to exist. Over the centuries, the Daleks have built up a powerful military empire spanning many star systems, mercilessly attacking other races and exterminating whole populations whilst enslaving others. Their unparalleled aggression has led to the devastation of entire worlds and even caused other races that generally mistrusted one another to form alliances with each other out of mutual fear of the Daleks.
Throughout their history, the Daleks' conquest of the universe has been impeded by the renegade Time Lord known as The Doctor. The Doctor has interfered with many of the Daleks' major military campaigns and even tried to prevent their creation on one occasion, and so the Daleks have marked him as their greatest adversary.
Though considered fearsome and deadly within the Doctor Who universe, the Daleks are often considered to be comical in their appearance and mannerisms by modern viewers. While portrayed as the ultimate warrior race, the design of their armoured shells can be viewed as nonsensical; their singular eye-stalks provide them only a narrow field of vision, their manipulator arms resemble toilet plungers and their lack of legs once prevented them from pursuing their enemies up stairs. They were also prone to being killed off in rather humiliating ways, such as simply being pushed off ledges. Since the 2005 reboot, the Daleks have become significantly more dangerous; they are now capable of levitating and flying and their foes are incapable of physically touching them without risking being incinerated by the Daleks' protective energy shields. Such shields also protect the Daleks from almost any conventional weapons, save artillery-grade ballistics or energy-based weapons. Nonetheless, the Daleks have a tendency to die off in droves whenever they encounter the Doctor who tends to find unconventional methods of defeating them. In many Doctor Who stories, the Daleks have been brought to near-extinction as a result of the Doctor's actions.