The Ninja Poke-Showdown - S1-E32
Continuity mistake: When Misty asks, "Brock, what kind of crazy place is this?" her bag is under and next to her, but in the next shot, it's not under her and is 0.33 metres away from her. (00:03:24)
The Ninja Poke-Showdown - S1-E32
Continuity mistake: When Pikachu tries to remove the webbing on himself, part of Charmander's yellow underbelly turns orange, like the rest of his body. (00:15:35)
The Ninja Poke-Showdown - S1-E32
Continuity mistake: When Ash asks Aya to remove him from the wall, Misty's blue eyes turn white. (00:07:19)
The Ninja Poke-Showdown - S1-E32
Continuity mistake: After Aya slaps Brock, Misty's bag disappears. (00:06:52)
The Ninja Poke-Showdown - S1-E32
Continuity mistake: When Ash and his friends notice a Venonat, Ash's bag disappears. (00:03:34)
The Ninja Poke-Showdown - S1-E32
Continuity mistake: When Brock opens the door to the mansion, he is to the right of Ash, while Misty is to the left. But in the next shot, they swap places. (00:03:02)
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.