The Kung Fu Master is, simply put, a kung fu master. He wears orange clothes, a black belt, and grey boots. He's got white hair in a bun, super bushy eyebrows, and a long beard. He's got all of the Asian stereotypes!
He appears in the intro of S04E09, kicking Eric in the face, making him bleed. Eric attempts to punch the master in the face, only to end up hitting a mirror somehow. Eric freaks out from this, making the master laugh with glee.
The master only appears in S04E09, for better or worse.