The Kaled scientist Davros is responsible for one of the greatest evils ever to be inflicted on the universe: the Daleks. Originally created as simple engines of war to eliminate the Thals, the Kaleds' rivals on the planet Skaro, the Daleks have gone on to terrorize the universe. Yet they are beaten time and time again by the Doctor; they even lose their centuries-long war with the Movellans, who develop a virus that is deadly to Daleks. It is the weaknesses of the Daleks that bring them back to Davros, who in turn needs the Daleks to satisfy his lust for power.
Although Davros is a genius, he is clearly quite mad. But his madness makes him the most dangerous paranoid megalomaniac in the universe. He is determined to eliminate the weaknesses of the Daleks and bring his creations back under his control, and he has no compunction about killing or crippling people in the course of his scientific experiments. He is as ruthless and cruel as the Daleks, although he still has vestiges of benign emotions which enable him to manipulate other people through pity.
The Daleks are now split into two factions: the original or Renegade Daleks and Imperial Daleks. Renegade Daleks are those created by Davros's original genetic experiments; Imperial Daleks are the more advanced Daleks that Davros is currently experimenting on to produce the ultimate fighting machine. Mutants that Davros produces which are unsuitable as Daleks are rejected and consigned to the outside world to survive on their own. These mutants usually stay near to Davros's laboratories, making fearsome guards.
Davros rules the Imperial Daleks in the guise of the Emperor Dalek. A cripple, Davros was already confined to an armoured, self-powered chair before his creations turned on him. This base is like the bottom half of a Dalek, with black panels and silver hemispheres in rows on each slab. It contains his life-support system, communications equipment, and even a few dirty tricks to overcome enemies. As Emperor, Davros has simply topped this base with a broad dome, about 1.5 metres in diameter, with a single eye-stalk. The front of the dome can be lifted to reveal Davros himself.
His wrinkled, brown-skinned and hairless head is surrounded by a cage of electrodes. In the centre of his forehead, suspended by the cranial cage, is a blue electronic eye which allows Davros to see: he is otherwise blind. His upper body is covered by a black, plastics tunic. One arm hangs uselessly by his side, the end disappearing into the top panel of his armoured chair; his right arm and hand control the switches and buttons. Davros's voice is electronically augmented, and sounds like the harsh, metallic voice of a Dalek.