I translated and reworded this guide from the forum on the german server in the hope to maybe help a little bit with basic ideas of how to kill the chaos giant. I hope everything in it is correct.
Slots:
1 spirit, 1 atshi, 4-5 antichaos scrolls, 3-4 slots mana scrolls (depending on your type of armor hence type of magic)
If you have less than 10 slots just adjust the number of slots while you should stick with 1 spirit and 1 atshi as you'll get buffed in the fight that allows you to crit hard which will allow heal you for more than the damage you take.
The chaos giant can put a spell on you which drains your mana and refills his own - remove this effect as soon as possible as it allows him to call more chaos monsters. It seems he even calls more monsters if you're completely out of mana.
The actual fight:
- Don't block! (The Defilers heal if you are fighting them in block - a good thing to remember for gates of chaos
)
- Don't summon your steeds because they lead to chaos monsters duplication (Cerrador and Jakarals in the beginning of the fight can be helpful though)
If you are out of chaos scrolls - time out! otherwise the chaos giant gets mana back like mentioned above.