A Ninja Boy (Japanese: ニンジャごっこMake-believe Ninja) is a type of Pokémon Trainer that first debuted in the Generation III games. They appear as little boys dressed as ninjas. They conceal themselves in the landscape and ambush passing Trainers.
A Ninja Boy named Kinji is seen battling Gentleman Robert in the Battle Dome in the Emerald chapter. While it is unknown who won, what is known is that Kinji at some point lost a match, eliminating him from the tournament.