• English / United States: Lefty
• Japanese / Japan: レフト
• Japanese (Romanized) / Japan: Left
• Japanese (TL) / Japan: Left

Lefty is one of the arms of Binacle. It left with Locke and became part of the masked persona Master Thief Keyes (Mysterious Knuckle) in an attempt to show Ed that they'd become a very good locksmith duo. Locke targeted multiple locks created by Ed. He would pick and unlock them but wouldn't actually steal any of the contents inside.

Righty got mad at Ed when he decided that he wasn't going to look for Locke. Righty had attached itself onto Bonnie after the break-in at the hotel as it was trying to find Locke and Lefty. After reuniting in the hotel hallway, Ed allowed Righty to stay with Bonnie for a day while they went looking for Locke and Lefty.

Once they found them, Righty returned to Ed to bring him to the Pokémon Center which was on fire and Locke and Lefty were trapped inside. It helped put out the fire by using Water Gun. It was reunited with Lefty some point after Lefty was taken with Locke to the police station for question.