Emperor Type 1

Despite not being a Dalek himself, (TV: Resurrection of the Daleks) Davros, the Kaled scientist responsible for the creation of the Daleks, was housed in a distinct casing during his time as leader of the Imperial Daleks, designated the Emperor Dalek. (COMIC: Emperor of the Daleks!, TV: Remembrance of the Daleks)

Characteristics
As Emperor Dalek, Davros' operated a casing coloured mostly white with gold livery, matching the Imperial Daleks he commanded. The casing was composed of a lower travel unit with gold sense globes, which appeared identical to those of the Imperial Dalek drones. However, what distinguished the casing was its top half; rather than a standard dome atop the upper grating section and middle section, Davros' body was housed within a large, spherical dome similar to earlier Emperors, such as Davros' immediate predecessor and the Golden Emperor. Unlike his predecessors, Davros' casing completely lacked the middle weapons platform and so sported no manipulator arm or gunstick. The dome itself was adorned with a pair of Imperial Dalek luminosity dischargers, however, it lacked the standard Dalek eyepiece; in its place was a silver hexagon with black outlines. A split between the hemispheres enabled Davros' to open up the dome, thus exposing himself, at will. (TV: Remembrance of the Daleks)

Following the Shoreditch Incident, Davros' casing was modified, keeping the lower half of his Imperial Dalek casing mixed with the top half of the Dalek City Emperor fought by the Second Doctor. (AUDIO: Terror Firma)

History
Returning to Skaro from Spiridon, Davros successfully usurped control of the Dalek Empire from the existing Emperor Dalek, only to be gravely wounded by Abslom Daak, who used his chainsword to cut Davros' life-support chair in half. Following this, what remained of Davros' body was salvaged by his loyal Imperial Daleks, who housed him within a specially made casing as he was named the new Emperor Dalek. (COMIC: Emperor of the Daleks!)

It was from within the casing of the Emperor Dalek that Davros led the Daleks from the Imperial Dalek mothership during the Shoreditch Incident. Contacted by the Seventh Doctor, Davros opened up his dome to reveal himself in their televisual meeting. Soon after, Davros was forced to use an escape pod to evacute the mothership, which was destroyed by the Hand of Omega. (TV: Remembrance of the Daleks)

By the time of his confrontation with the Eighth Doctor, Davros' casing was modified. He himself teetered on the edge of sanity, his mind split between two warring personalities — Davros and "the Emperor", with the latter ultimately prevailing. (AUDIO: Terror Firma)

By the outbreak of the Last Great Time War, however, a new Emperor ruled the Daleks. (PROSE: Birth of a Legend) Meanwhile, Davros, back to his original personality, remained an asset to the Daleks, with his chair being reconstructed. (TV: The Stolen Earth)

Other references
Following the Shoreditch Incident, the Seventh Doctor encountered another Emperor Dalek whom he mistook for Davros. (COMIC: Nemesis of the Daleks) This Emperor was infact Davros' immediate predecessor. (COMIC: Emperor of the Daleks!)