The Chaos fight has 6 stages. He is tethered inside the circle of crystals which will damage the nearest person to them. If a player dies during the event, two adds will spawn per death.
Show Spoiler hide_message
'''Stage 1''' 100%-90% ~ Chaos starts with melee and a curse. The curse will be cast on three random players and will kill them if not cured.
'''Stage 2''' 90%-79% ~ Same attacks as above and he starts casting Meteor Strike.
'''Stage 3''' 79% ~ Chaos will stop all his attacks, goes invulnerable and will summon 4 Reapers of Chaos. These eyes will head for the healers in the raid and can kill them in one round. They cannot be killed and will remain up for a limited time. Chaos does not summon while the Reapers are up. He will, however, continue cursing your raid (even though you're running to avoid the Reapers. Make sure you have a quick way to remove curse to continue running.
'''Stage 4''' 79%-55% ~ After the Reapers of Chaos disappear, Chaos will continue his melee attack and curse.
'''Stage 5''' 55%-34% ~ Chaos adds a Knock-back to the continuous cursing, which stuns (and interrupts curse removal). Around 50%, he will mana drain the entire raid.
'''Stage 6''' 34%-0% ~ Chaos will go invulnerable and stop his melee attack, however, continues his curse and AoE knockback. You must now engage the six perma-rooted crystals surrounding Chaos. You will complete the fight once the last crystal is destroyed.