• English / United States: Dario
• Japanese / Japan: ドリオ
• Japanese (Romanized) / Japan: Drio
• Japanese (TL) / Japan: Drio

Dario is a nefarious boy who lives in the same village as Lara and he hired Team Rocket to cause an 'accident' to remove Lara from the Pokémon race so he would have a better chance at winning himself. He boasted to Lara Laramie that he was going to win the race but Lara Laramie retorted and told him that the race couldn't be won on just speed alone. Misty thought Dario was quite despicable even before she knew that he was in cahoots with Team Rocket but Lara Laramie explained that he was a pretty skilled competitor.

Team Rocket managed to stir up Lara Laramie's Tauros and Dario quickly showed up in town making it look like he was being helpful by telling her that something wrong with her Tauros. Team Rocket spooked Lara Laramie's Ponyta and Lara Laramie ended up injuring her arm. Dario reported in with Team Rocket and complemented them on a splendid technique as no one suspected that he was responsible for Lara Laramie being out of the race Pokémon.

During the Pokémon race, Dario raced on his Dodrio and Team Rocket continued to help him try to win the race by laying traps to knock out his competition one by one. Dario lead the race for almost the entire time but he revealed half way through the race to Ash Ketchum and Misty that Team Rocket was working for him and that seemed to motivate them to make sure one of them one the race instead of Dario. In the home stretch, Dario ended up loosing the race at the finish line to Ash Ketchum and Lara Laramie's Rapidash but Dario was a poor sport and a bad looser and he decided to attack Ash Ketchum and Lara Laramie's Rapidash but Lara Laramie's Rapidash ended up kicking Dario and Dario's Dodrio off into the distance.