The Supreme Dalek was the second in command of the New Dalek Empire in 2009. It was Red with gold bumps and Extra plates around its casing. It had a slightly deeper and elegant voice than the other Daleks and ranked directly below Davros.
As well as extra armour plating, the Red Dalek had an extra dome light which-as with its other lights- was mounted on a small plate.
It commanded the invasion of Earth during the War in the Medusa Cascade and reported its victory to Davros though he was only interested if The Doctor had arrived. The Supreme One stated that there was no sign of Time Lord activity and that they were beyond the Doctors reach which fascinated Davros as it sounded as a declaration of victory which was impossible as the Daleks were elevated above emotion.
Regardless the Red dalek has a clear dislike for Dalek Caan, calling him the abomination.