Dalek Emperor (The Twelfth Doctor's been Timejacked!)

The Twelfth Doctor stated that a Dalek Emperor held leadership of the Daleks during his life. According to him, the Emperor had launched a plot to use the internet to convert the people of the 21st century into Dalek drones, which was something he needed to put a stop to "sooner or later". The Emperor wore a Emperor Type II casing. (WC: The Twelfth Doctor's been Timejacked!)

The Fourteenth Doctor later questioned if an Emperor was leading the 1966 Dalek invasion of Earth. However, the invasion was actually under a Supreme Dalek. (COMIC: Liberation of the Daleks)

Behind the scenes
The concept of a Dalek Emperor in a Emperor Type II casing who is contemporary to the Twelfth Doctor was first seen in LEGO Dimensions.