QC quite simply stands for 'Quality Control', and has to do with checking to see if a new area entry is fit to enter the world of Viking.
There are usually at least two Arch Wizards with a main area of responsibility in the QC-department. Their job is to thoroughly check the code of the area entry, and to decide whether or not to accept it, thus making it a part of the world.
The current Arches within the QC-department (command 'arches'):
Main QC arches: Gaeius (admin), Crovax (arch) and Postkasse (arch)
Secondary QC arches: Khaine (arch), Kralk (arch)