AQW - How to get Celestial Champion achievement

To get "Celestial Champion" achievement first you have to go to celestialarena (type /join celestialarena in your chat bar).

Now you have to complete all the quest from "Aranx".
These quest aren't too hard. You just have to kill some bunch of monster boss. It would be great if you have good class that can solo the boss.
After that you will get a final quest.

You have to defeat Aranx to complete the quest.

Done! You'll get the achievement. Enjoy!