Little is known about the red Supreme Dalek. Dalek Caan went back in time and saved Davros from the Time War, then he created a new race of Daleks. In The Stolen Earth Davros is shown to fear the Supreme Dalek.
This Dalek only appeared in the 2008 TV story The Stolen Earth.
Pictures above are from the TV story titled The Stolen Earth
Take them to the Vault. They are the playthings of Davros now.