It is going to be interesting to see how well Chaos, aside from actually fighting and winning the game, can go for some outright wins by putting a warlord down. If nothing else, it may force an opponent to change tactics by having to run his warlord away from massed damage or risk losing the game right there and then.
Sadly, Zarathur may be one of the Chaos factions biggest weakness. Sure he is pretty strong, but you need to keep him at a planet for his ability and He has the lowest HP (I believe anyway) of all of the warlords. It takes one good slam of 3 damage for the chaos player to really play timidly, which could destroy your strategy.