|~ Butch's response to whoever mispronounces his name|
|~ Butch to Jessie and James|
In the Japanese version, he was voiced by Takehito Koyasu. In the English version, he was initially voiced by Eric Stuart, and later by Billy Beach.
Butch's partner is Cassidy, and she is one of the few that usually manages to get his name right, much to his frustration. In one of the most famous running gags in the anime series, everyone else calls him either "Biff", "Bill", "Buffy", "Bob", "Hutch", "Butcher", "Patch", "Botch", "Chuck", "Footch" or "Hootch" among others (コサンジ, Kosanji in Japanese). Sometimes, when she gets it right, he, by habit, tries to correct her and stops and realizes that she got it right. Another time, he called himself by the wrong name when attempting to correct someone when they got it right. This, of course, annoys him to no end, so much so in the Pokémon Chronicles episode Training Daze he said in frustration, "That's it, I'm changing my name".
He and Cassidy are shown to hate Jessie and James, as they think of them as embarrassments to the organization. However, just like them, Butch can be quite cowardly and bumbling, as his and Cassidy's plans to steal Pokémon have failed miserably, which took a toll in his pride as he tearfully states that he and Cassidy will never amount to anything.
Like his partner, Cassidy, Butch is proud of his rank and popularity. He has an issue when people doesn't get his name right that includes Cassidy. He is disrespectful towards Jessie, James and Meowth who he and Cassidy considered to be losers due to their low ranks and failures of capturing Pokemon and proven to be superior to them by calling them Messy and Lames in Pokemon Chronicles. He hold a strong loyalty toward Giovanni and Professor Namba who they trusted him and Cassidy.
He first appeared in The Breeding Center Secret, where he and Cassidy build and advertise a fake breeding center to steal Pokémon. To further their goals, they framed Ash and his friends, as well as Jessie, James and Meowth, resulting them to be arrested. However Misty, Pikachu, and Psyduck gather enough evidence to prove her friends' innocence, resulting both Cassidy and Butch to be arrested while Jessie, James and Meowth escape from prison.
Butch returned again Pikachu Revolts, where he and Cassidy were bailed out by Giovanni and started a new plot to steal more Pokémon at Mandarin Island by using a Drowzee to turn all of the island's Pokémon against their trainers. However, they made a mistake in turning Jessie and James' Pokémon against their trainers, resulting an angry Jessie and James to briefly team up with Ash and his friends. Jessie, James, and Ash enter into a battle against Cassidy and Butch, which ended when Misty's Togepi uses Metronome to defeat Drowzee, resulting all the Pokémon to be free from Drowzee's control and Cassidy and Butch to be thrown back into jail, much to their dismay.
Butch appears in the Lugia story arc, where he and Cassidy teamed up with Dr. Namba to capture Lugia and its child. However, both Cassidy and Butch end up having a battle against Jessie and James (who attempt to beat them to it), but their battle frees Lugia, who then blasts both duos and their Pokémon into the sky.
Butch returns as a recurring antagonist in Pokémon Chronicles, where he and Cassidy try to steal Pokémon for Dr. Namba's new secret project. Similar to Jessie, James and Meowth in the anime, Cassidy and Butch serve as comic relief in the spinoff series, as they failed everytime to steal Pokémon and get blasted off in the end, much to their complete embarrassment and distraught.
- In Japanese version, when his name is mispronounced, he is called Kosanji. The word kosanji (コサンジ) means mistake in Japanese.