Emperor Type I

By the time he presided over Operation Human Factor, the original Dalek Emperor was housed within a huge casing. (TV: The Evil of the Daleks) Time Lord historians at the time of the Last Great Time War designated it as the "Emperor Type I", (PROSE: Dalek Combat Training Manual) while earlier human historians dubbed it the "Emperor Type 3". (PROSE: Dalek Survival Guide)

Characteristics
The Emperor Type 3 was "about 30 feet high" and "plumbed into" the corner of its control room in the Dalek City on Skaro. (PROSE: Dalek Survival Guide) The casing had no weapons, instead having two pale sense globes where its weapons platform ought to be. Its base was also divided in hexagons instead of purely vertical slats. A skipped row separated the two pale sense globes from a ring of black ones. The dome was also atypical, being "stacked" with a smaller dome upon the main one, (TV: The Evil of the Daleks) resembling the body of a Chumbley. (TV: Galaxy 4)

From within this casing, the Dalek Prime had an increased telepathic capabilities, able to read minds and control them. (COMIC: The Brain Tappers, AUDIO: The Ultimate Adventure)

Origins
Over time, the Dalek Emperor's original casing became damaged. This first became apparent during the 2415 Dalek invasion, when the Emperor's time machine proved "faulty" and sent him on a long, strenuous journey through human history before he could find his way back to his own era and the rest of the Dalek Empire. Shortly later, his sonic guards were cracked during the Invasion of Uranus by human colonists using supersonic waves.

The faulty Emperor's failures piled up, and were ultimately called out by the Red Extra-Galactic Squadron on the occasion of the Super-Skaro year. Though the Black Dalek Leader exterminated the Squadron's leader for its insolence, the Emperor admitted that he was faulty, and had Scientist Daleks take him apart to try and find the flaw. Reviewing the damage and also the digital memory cells contained in the casing, the scientists realised what had happened. (COMIC: The Secret of the Emperor)

Trading in mobility for increased mental capabilities thanks to an augmented electronic brain that hooked into all the Dalek City's systems, the Dalek Emperor mutant had himself transferred out of the sphere-headed casing and into a huge, towering one in the Great Hall of the City. (COMIC: The Secret of the Emperor, PROSE: The Evil of the Daleks) According to another, slightly different account, the change was prompted by the simple fact that the Emperor mutant had grown far larger as a result of the experiments he had been conducting on himself to expand his organic brain's mental capacities. (PROSE: The History of the Daleks)

At any rate, it was in this casing, dubbed the Emperor Type 3 by the Dalek Survival Guide (PROSE: Dalek Survival Guide) and the Emperor Type I by the Dalek Combat Training Manual, (PROSE: Dalek Combat Training Manual) that he oversaw the plot to distill the Human Factor and the Dalek Factor. (TV: The Evil of the Daleks)

Use by the Dalek Prime
In this new casing, the Emperor was able to read thoughts. He attempted to exploit this during an attempted attack of Earth. However, Sara Kingdom realised his new telepathy-based strategy. She ordered the rest of the fleet to attack the Emperor's ship while giving a flawed version of the plan to the Space Security Service's officers. The Dalek fleet was scattered and almost wiped out, with the Emperor returning to Skaro. (COMIC: The Brain Tappers)

Allying with the Cybermen, specifically a group of CyberNeomorphs under a Cyber-Leader, and a group of mercenaries led by Karl, the Dalek Emperor and a force of Silver Daleks in war machine casings plotted to compromise a peace conference on Earth during the late 20th century by brainwashing an American envoy, who would be armed with a Dalekanium bomb. Whilst the Emperor at one point claimed they would destroy the Earth, the Daleks intended to rule over the planet after the disturbed peace conference caused the major powers to declare war on each other, weakening the planet for a Dalek invasion.

In truth, the Cybermen and mercenaries were mere pawns to the Dalek plot, which called for the Galactic Council to assume only those groups had attacked Earth. With them blamed, the Daleks would be free to exterminate them without needing to be publicly involved in the attack on the peace conference. Recording his discussion with the Emperor in secret, the Sixth Doctor played audio of the Emperor's plan to the Cybermen and mercenaries, turning the Daleks' supposed allies against them. He then freed the envoy from the Emperor's brainwashing, halting the Dalek plan. (AUDIO: The Ultimate Adventure)

The Human Factor plot
Desperate to win the Great War, the newly-rebuilt Dalek Emperor ordered the Daleks to conduct research into the Dalek Factor. (PROSE: The Evil of the Daleks)

He ordered the Daleks to capture the Second Doctor so that they could force him to conduct research into the Human Factor. This would unlock the secrets of the Dalek Factor which was to be spread throughout all areas of human history, giving all humans the mentality of a Dalek and preventing the Great War from ever happening. When the Doctor escaped, the Emperor was caught in the chaos of a civil war between humanised Daleks and un-altered Daleks and nearly destroyed. (TV: The Evil of the Daleks) "Trapped inside its casing, unable to speak or kill," the Emperor watched the Second Doctor leave the planet. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe )

Aftermath of the Dalek Civil ar
Although its casing had been heavily damaged (TV: The Evil of the Daleks) with the huge mutant even falling out of it and into a sizzling pool of burning liquid, (PROSE: The Evil of the Daleks) the Emperor survived. Shortly after the battle, the Emperor met Bernice Summerfield as she moved through time, and questioned her on why the Civil War had occurred and why the other Daleks questioned him. She berated the Emperor during their short discussion, mocking him for not even having a gun, and walked away so that she would live, giving "the greatest insult [she] could think to give a Dalek". The Emperor was left screaming after her for her to obey him and that she would be annihilated. (AUDIO: The Lights of Skaro)

The Second Doctor soon encountered Daleks who brought news of the Emperor's survival; (COMIC: Bringer of Darkness) at some point, Jamie McCrimmon and Victoria Waterfield returned to the Dalek City themselves; sneaking into the silent, darkened throne room, they were shocked to find that they had walked into the lion's den, with the Emperor alive and well and more Daleks than ever standing guard above him, who triumphantly declared that "the Daleks [had] returned". (HOMEVID: Emperor of the Daleks)

Undated events
At some point, the Doctor encountered "a Dalek Emperor" of this casing type, who did not seem to be the sole ruler of the Dalek Empire. (PROSE: The Dalek Factor)