Black Belt

A Black Belt is a Trainer class that debuted in the Kanto region. They are generally depicted as generic martial artists, in headband and gi striking a fighting pose. They (obviously) specialize in Fighting Pokémon.

Black Belts are the male counterparts of the Battle Girl class. When paired with Battle Girls or male Psychics in Double Battles, they are called Battle Kin or Body & Soul, respectively.

In Pokémon University, when the player gains access to Johto, they find the Karate King (originally from the Fighting Dojo in Kanto) and its disciples beyond the Waterfall inside Mt. Mortar. He subjects the player to the Black Belt Gauntlet, in which they must face their Black Belt disciples in a row, and in the end, the Karate King himself.