Airmd vs Hinoarashi! Wings of Steel!! - S3-E36
Continuity mistake: When Brock says that Growlithe must have lost a challenging match, part of his top right pocket is visible past his right strap, but in the next shot, it is not. Also, his left strap is closer his left sleeve, but in the next shot, it is closer his collar. Additionally, there is a crease on the right side of his vest, but in the next shot, there is not. (00:01:26)
Answer: He is a good guy but just found himself in a bad situation when he worked for Lysander. He didn't want him to harm Ash and his Pokémon when he was trying to get the special bond between Ash and his Greninja to work. He does leave Lysander and go back to being a good person.