I've finally started work on my Chaos Marines to do list and this is the beginning; one Chaos Sorcerer. He has the mark of Tzeentch (although I'm not happy with the one I painted so I'll try again until I'm satisfied).
I've decided to paint him as one of the Thousand Sons but pre-heresy colours. The reason for this is that their background doesn't mention anything about them changing their armour paint like the other chapters and originally they wore red armour. Plus I like the red armour, it contrasts more with the blue of the lower clothing. I chose blue to keep in with the Egyptian theme of the unit; blue, red and yellow being very common colours in Egyptian ceremonial clothing.
The eye on the shoulder represents the Athanean cult (telepaths) of the Thousand Sons legion and as he'll always have at least a mastery level of 2 he can use a telepathy power to really hammer home the point. I'm sure the Athanean cult eye wasn't a real eye but I've decided that the Warp has altered it into a real eye.