The character is played by Sjo. He's dressed in all black and wears a mask on his face; it has not been revealed what his face looks like. Although he only speaks Japanese, nobody seems to have any problems understanding him. In the first episode he says that his name is ショ, pronounced "show".
The Ninja is a martial arts expert and a master swordman. He is also quite naive and credent. His clan, the くそくび (kusokubi) clan, taught him to hate the pirates but after meeting one he actually quite likes him. They play a lot of games and fight when one of them loses.Because of his mask he rarely drinks or eats in public. At the end of Pirate vs Ninja 3 he drinks some rum from the pirate and passes out.
His master, Kusokubi Sensei, was accidentally assassinated by a secret agent codenamed Bob the spy. Sho might take his revenge if he remembers it.