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/Lao is seen battling Gentleman Walter in the Battle Dome in the Emerald chapter. While it is unknown who won, what is known is that Lao at some point lost a match, eliminating him from the tournament.