Be Careful with the Crit Ring Quests.....

If you don't talk to cassandra for 9 levels after reaching a level of a multiple of 10 (for example, if you go past 29 without talking to her after hitting 20), you won't be able to get the ring because the quests for every 10 levels is a prerequisite for the next, and you get the quest has ended due to an unknown error notice if you try to complete it outside its level range.