Qingzi is in the FB 29 area accessed in the room just 'south' of the most 'northern' room of the Secret Passage (north of Archosaur at 559, 765) A party of at least lvl 40's should be able to kill Qingzi easily. Qingzi has an unusually powerful Earth-based spell, which can kill many characters outright. Since it is magic damage, one of the better types of tanks is a Wizard with good earth defense armor, and their special class ability of earth barrie. Another option is Venomancers, who can heal other Venomancer's pets, sharing the healing of a single pet tank.