Dr. Namba works as a scientist in Team Rocket. He first appeared in Oaknapped, where he kidnapped Professor Oak to get more information about Pokémon, but Oak was rescued and his plan failed. He was trying to capture a Lugia in The Mystery is History, A Parent Trapped and A Promise is a Promise, but failed once more. He appeared in many other episodes assigning Butch and Cassidy their missions. A running gag with Dr. Namba was that others kept pronouncing his name incorrectly, which he greatly disliked.
Dr. Namba appeare in Let's Save the Lugia! and was referred to as a Team Rocket Scientist in that chapter.
Hitmontop is a Pokémon belonging to him. He had a battle with Ash's Pikachu and dealt tons of damage to him. Hitmontop wearing the Rage Crown that made him stronger.
Hitmontop's only known move is Rolling Kick.
Gastly is another Pokémon belonging to Dr. Namba. None of Gastly's moves are known.