• English / United States: Leon
• Japanese / Japan: レオン
• Japanese (Romanized) / Japan: Leon
• Japanese (TL) / Japan: Leon

Leon is an evil villain that saw Ash's Pikachu and Meowth as good targets to steal because they were rare in the Isshu region. Leon's character design is a clear reference to the "mechanic" character from the various Time Bokan series. Leon is also quite fluent in French.

Leon is a very eccentric character who borders on megalomania. He taunts its victims and dares them to try to attempt to catch him. Leon's Beheeyem is used to help him create dream world's and dream world layers which makes it difficult for his victims to figure out exactly what's going on which makes it a lot easier for him to escape.

Unfortunately for Leon, Psychic type Investigator Officer Jenny (Unova) had been hot on his tail and was investigating psychic instances and crimes. Officer Jenny (Unova) and her Jenny's Duosion helped rescue Ash's Pikachu, Meowth and Iris' Axew from Leon and arrested him.