The School of Hard Knocks - S1-E9
Revealing mistake: In the English dub, when showing the front of the flyer, it has filler text that is not related to what it is about. Also, its Poké Balls are slightly transparent and its picture can be seen through it. (00:05:43)
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.