Joe Dirtamancer is a Dirtamancer in the Magic Kingdom. He is Qualified, meaning that he can sit in judgment of other Casters. He describes himself as a 'rocker,' though how this term relates to his status as Qualified, a Dirtamancer, or both is unclear. He is responsible for the destruction of the Barrier that Sizemore Rockwell constructed in the Magic Kingdom.
Real World References
Joe Dirt is a movie starring David Spade, whose character strongly resembles the Dirtamancer.