Chaos HQ'sThe Champion of Chaos Rule:
This is something to bear in mind to start with if you are going for a combat lord. Anyone with this rule must challenge if in combat. This can be bad as your opponent can use this in some situations.
Chaos LordA solid choice, as he is cheap and has fearless as standard. He can be useful without any Mark of Chaos, if you want as he is able to join units of any god. The other big thing about the Chaos Lord is that he unlocks Cult troops as a troop choice. The main use of this seems to be either Nurgle to unlock Plague Marines, or a Slaanesh lord to unlock Noise Marines.
How would I Equip Him...?