Not one faction .... but 4 factions. Khorne, Nurgle, Slaanesh, Tzeench.

The outline unit list is pretty much as follows:

Chaos Marauder

Mounted Marauder

Veteran Marauder ( like the ordinary, but a bit nastier and 'touched' by Chaos )

Mounted Veterans

Chaos Warrior

Veteran Warrior ( mutated and a bit more Chaos Faction specific. ) These guys will be different for each faction, where the ordinary warriors are not. Casuir has started work on these, and they will be a bit more 'nasty' than the basic warriors.

Chaos Knights ( very nasty ) Mounted and foot versions..with a suitably chaotic steed!

Chaos Champions. Not strictly a unit in the true sense, but these guys will be in as small a unit as possible, and would represent the generals bodyguard. I also plan on using a variant of this model as a leader model for the lower rank units.

With the faction specific variations on the Elite units, we are looking at 17 units. Marauders will serve as crew figures for Chaos siege engines.