Dalek's History
The Daleks were a warrior race made up of genetically engineered mutants belonging to fundamental DNA type 467-989. By most accounts they were originally from the planet Skaro. The mutants were encased inside an armoured travel machine built from polycarbide and the metal Dalekanium.
On many occasions, the Daleks openly acknowledged a single Time Lord, the Doctor, as their greatest enemy. The Doctor described them likewise, and, in their tenth incarnation, stated that a Dalek was "not just metal, it [was] alive," that "inside that shell, there [was] a creature born to hate, whose only thought [was] to destroy everything and everyone that [wasn't] a Dalek, too. The Tenth Doctor also noted that from birth, the Daleks were encased in a cold metal shell unable to feel anything, claiming that was why they "scream[ed]. The War Doctor also said that Daleks were "not robots", but "savage, incredibly intelligent, living, breathing creatures housed inside a war tank".
The Daleks fought the Time Lords in the Last Great Time War, ending in the near-total destruction of the Dalek race, until they rebuilt their empire by using a progenitor. Intensely xenophobic and bent on universal domination, the Daleks were hated and feared throughout time and space. Their goal was to eradicate all non-Dalek life, as programmed by their creator.
Although the Daleks looked entirely robotic, they were, in fact, cyborgs, with a living body encased in and supported by an armed and mobile outer shell of Dalekanium and polycarbide protective metal armour. These were Mark III travel machines, designed to carry their mutant forms, and they were not truly integrated biomechanoids. In this respect, they were somewhat similar to a Cyberman; unlike them, however, the Daleks' bodies had mutated so drastically from their Kaled ancestors they had lost all humanoid appearance, save for one eye . The Daleks transmitted information using a sort of artificial telepathic network known as the Pathweb, which the Twelfth Doctor would later state to be the "biggest database [he knew]".
Daleks did not die naturally, every cell being genetically hardwired with an impulse to keep on living, even if they were chopped to pieces and left buried for centuries away from their casings. However, they did age, the body decaying further and further — eventually reaching a point where it was little more than mewling, hateful sludge of dark brownish colour. Incapable of steering their armour, such decayed Daleks would exit them and confine themselves to the sewers of Dalek cities, for which reason the Dalek word for "sewer" was also their word for "graveyard". One Dalek creature remained alive even as it was dissected by the scientist Bryant Anderson.
