One of the first Daleks, who exterminated Davros and proclaimed the Dalek's future victory over the universe, assumed the role of Dalek Prime (later Emperor) and would continue to act as the Emperor throughout Dalek history.
During the time that Davros himself assumed the position of Emperor, this may mean that two Emperor Daleks existed at the same time, opposing each other:
The Golden EmperorEdit
After the neutronic war that devastated Skaro, the mutants had survived in the casings. The only humanoid Dalek survivors of the war, Yarvelling and the warlord Zolfian encountered a Dalek that persuaded them to build more Dalek casings for their mutated descendants. Before the last two humanoid Daleks died, a special casing was built for the Emperor to reflect its new rank, made of Flidor gold, quartz and Arkellis flower sap. The Golden Emperor was slightly shorter than the other Daleks, with a disproportionately large spheroid head section and in gold rather than grey.
The Emperor within the Dalek CityEditThe next known incarnation of the Emperor remained in was an enormous immobile conical shell plugged into a corner of the control room in the Dalek City on Skaro and connected to the wall by tubes. It spoke in an echoing voice.
This Emperor was apparently destroyed by a civil war between Humanised Daleks and un-altered Daleks. However, a light was seen still blinking on its casing at the end indicating some kind of activity.
It is possible that this Emperor is Davros with his Dalek mind in new casing.
Davros as EmperorEdit
Davros was made into the Emperor of the Imperial Dalek faction of the Daleks. He was encased in a customised Dalek casing with a dome top which could open and close, his body below his head and shoulders covered in a mass of tubing and cables, implying that he had greatly deteriorated physically. He was last seen heading for an escape pod just before his ship was destroyed in the wake of the supernova (set off by the Hand of Omega) that consumed Skaro. Later, Davros' increasingly unstable mind was obliterated by a totally Dalek personality, that of the Emperor. This new Emperor then takes command of Davros's Daleks and departed.
The Emperor during the Last Great Time War Edit
A possibly different Dalek Emperor ruled during the Last Great Time War and was believed to have been destroyed at the end of the war. However its ship had barely survived the war, falling through time. Afterwards, it went into seclusion and went on to rebuild a new race of Daleks. This Emperor was a Dalek mutant floating in a transparent tank of liquid, topped by a giant-sized Dalek dome, complete with eyestalk, and flanked by panels of armour dotted by Dalek "bumps". Because this Emperor had recreated the Dalek race, it saw itself as a god, and had transformed its Daleks from fascists to religious fanatics centred around them worshipping it. The Emperor was apparently atomized along with the rest of the Daleks by Rose after she had absorbed the energies of the time vortex and became the Bad Wolf entity Temporal paradox in 200,100.
This Emperor was referred to as a mere scavenger by the Doctor.
At some point during the Time War the Emperor created the Cult of Skaro, a group above and beyond the Emperor, created to "think as the enemy thinks" and "imagine", all to aid in obtaining victory. In order to survive the Time War, the Cult stole a Time Lord Prison Ship carrying millions of Daleks and created a Void Ship. Calling the Prison Ship the Genesis Ark, they escaped into the Void, unaware of the fate that eventually befell the Emperor.
The Master faced the Dalek Emperor at least once after he was revived when the Emperor took control of the Cruciform during the Time War.