Stereo-Cassette King was a choujin based on a Walkman, and the weakest of Buffaloman's henchmen. He was the first of the seven evil chojin to fight Kinnikuman. He could load a cassette into himself which would give him the abilities of a certain choujin (among them Robin Mask, Ramenman, Brocken Jr., and Warsman). This led to his downfall, however, when he used an outdated cassette of Kinnikuman to finish Kin with his own moves, only to learn that despite his silliness, Suguru had greatly improved himself as a Seigi Choujin since beginning his career. Kinnikuman then defeated him with a Kinniku Buster.