Dalek Prime

A Dalek Emperor successfully conquered Mutter's Spiral centuries after the 36th century in what was known as the Second Great Dalek Occupation.

Kar-Charrat mission
The Emperor of the Daleks remained on Skaro whilst it sent the Dalek Supreme to take over the Library on Kar-Charrat. After the Seventh Doctor's apparent death before he was able to be interrogated, the Emperor ordered the Dalek Supreme to return to Skaro and self-destruct, replacing him with the Chief Scientist. With the library destroyed, the Emperor declared that he would devise an alternative plan. (AUDIO: The Genocide Machine)

Second Great Dalek Occupation
Upon learning of Project Infinity, the Emperor planned to hijack it to bring a victorious Dalek army to N-Space from a parallel universe. He had Vega VI invaded and the people begin mining veganite, disguising his ambitions by invading the rest of Mutter's Spiral. (AUDIO: Project Infinity) He monitored the conversations between the Dalek Supreme and Susan Mendes, planning on utilising her to improve the efforts of the workforce. (AUDIO: Invasion of the Daleks)

The Emperor made sure that Suz would not be exterminated except on his own order, although he was aware that her unique position might compel her to act against the Daleks. (AUDIO: The Human Factor) He allowed Suz and Kalendorf to be made aware of his and the Dalek Supreme's suspicions, knowing that it would motivate them to redouble their efforts to prove their loyalty. (AUDIO: "Death to the Daleks!")

With the veganite on board, the Emperor headed to the Lopra system before Suz's rebellion. He was almost killed when Kalendorf and the Seer of Yaldos linked minds with Mirana and struck back at him, giving Kalendorf a brief look into his mind. The Emperor recovered and took control of Project Infinity, finding a suitable universe and bringing through the alternate Daleks who attacked upon learning of the Emperor's Daleks many crimes. (AUDIO: Project Infinity)

Within Susan Mendes
In the first battle of the Enemy-Alliance Dalek War, on Lopra Minor, the Emperor was captured by the Earth Alliance and became totally inert, transferring his consciousness into Suz (AUDIO: Dalek War: Chapter One) as he knew that Alby Brook would save her. (AUDIO: Dalek War: Chapter Three) His body was taken by the Mentor to a secure location (AUDIO: Dalek War: Chapter One) whilst his Daleks took possession of his casing.

The Daleks took Suz and scanned her, briefly reawakening the Emperor. (AUDIO: Dalek War: Chapter Two) They completely wiped Suz's personality, giving the Emperor complete control, and he tortured Kalendorf to learn of his plans, focusing all of the Daleks' mental energy into him. Kalendorf was able to restore Suz momentarily with his telepathic powers, allowing her to cause the Great Catastrophe and kill the Emperor. (AUDIO: Dalek War: Chapter Four)

Personality
The Daleks believed that the Emperor had the greatest mind in the universe. (AUDIO: Project Infinity)