Ryou

Aaron was briefly mentioned by Lucian in An Elite Meet and Greet. However, Aaron made his actual debut appearance in A Trainer and Child Reunion! where he was shown to be preparing for his championship battle against Cynthia. Finding out that Ash and his friends know Cynthia personally, he took them to his training center. He also reveals that a Wurmple was his first ever Pokémon and friend when he was young but due to his anger at it for losing a match, he abandoned it. He regretted it later and from then on tried his best to train hard and to understand Bug-type Pokémon so that the same incident would not happen again.

He eventually encounters it again as a Beautifly at the end of the episode, following a battle against Team Rocket. He was seen again on television, one episode later, having his battle with Cynthia. It was also shown that he had lost the match.