Kid Muscle is the main character from the anime and manga series Ultimate Muscle, which is a sequel to the original Kinnikuman. He is the son of the legendary wrestler Kinnikuman and possesses superhuman strength and abilities, making him a formidable competitor in the wrestling world. In the series, Kid Muscle battles various opponents, including other wrestlers and villains, to protect the Earth and uphold justice. His character is known for his goofy personality, determination, and the ability to learn from his experiences, which helps him grow as a wrestler and a hero.