Great, but twisted and crippled, Kaled scientist.  Davros was permanently attached to a mobile, life-support chair.  His vision, and probably his other senses as well, were replaced by mechanical aids.  He had also lost the use of his left arm.

Davros was Chief Scientist of the Kaleds and the person responsible for the creation of the Daleks.  He studied and further developed some of the mutations resulting from the Neutronic Wars, then created a mobile casing for them and christened his new creatures Daleks. The Daleks’ mobile casing was based on Davros’s own life support chair. 

Davros fought against the Fourth Doctor, who had been sent by the Time Lords to Skaro to stop the creation of the Daleks, and even plotted the destruction of his own people to further his creations.  Davros was eventually blasted by the Daleks, who turned against him, and was left for dead in the Kaled bunker (4E). 

The Daleks brought Davros back to life in the 27^th Century, when they needed his help against the robotic Movellans.  But, thanks to the Fourth Doctor’s intervention, Davros was captured  life support chair.  Earlier versions were powered by static electricity.  Latand sent to Earth to be tried (5J).  Davros was then sentenced to life in suspended animation in a space prison.

 Ninety years after his trial, Davros was freed by galactic mercenary Lytton, who had been hired by the Daleks, who again needed their creator’s help against a Movellan-designed virus. 

Davros then decided to create a new race of Daleks, subservient only to him.  But his plans were thwarted by the Fifth Doctor.  Afflicted with the Movellan virus, Davros was thought to have died in the destruction of the space penitentary (6P).  However, Davros had survived.

Under the identity of the Great Healer, he took over the Tranquil Repose mortuary on Nekros, where he used human bodies in

suspended animation to finally create his own army of White (or Imperial) Daleks.  But the Sixth Doctor defeated him.  Betrayed by an employee of Tranquil Repose, Davros was captured by the Daleks and taken back to Skaro (or Skaro II) (6Z). 

Davros resurfaced again, about 2963 AD. Leading his White Daleks, and using the identity of the Emperor Dalek, Davros used the Daleks’ time corridor technology to travel back in time to 1963 London to capture the Hand of Omega.  There, he fought the regular Daleks, led by a Black Dalek.  As a result of the Seventh Doctor’s intervention, both Dalek races were utterly devastated.  Either Skaro’s, or Skaro II’s, sun was destroyed.  However, Davros escaped again (7H). 

It is possible that Davros finally achieved his dream of reclaiming control over his creations.  The Emperor Dalek of later years may very well have been an evolved version of Davros (LL).