Chaos faction is all about power and offense. Chaos wants to devour all order and turn it back to the primal form.
Chaos domain is the Maelstrom - a mobile base that changes it's location dynamically based on how many players are online (the actual calculation is an average between the last hour average and a predicttion of the next hour average based on the next from the same day last week; first week it won't move at all). The city periodically spawns rifts that are both two-way portals across the world that serve as a temporary mobile base and place to requisition equipment and restore life.
Only chaos players are able to stay inside a rift/maelstrom without suffering negative consequences. As the game progresses, other factions will learn ways to at first resist and eventually completely negate this effect allowing them to attack maelstrom itself.
Chaos players outside maelstrom gradually become more vulnerable and eventually start losing life. This effect can also be mitigated and eventually ignored based on tech levels.
Chaos players have FFA PVP on all the time everywhere except inside the maelstrom.
Chaos players start without weapons but their hand-to hand attacks are more powerful (claws and talons).