• English / United States: Billy
• Japanese / Japan: ビリー
• Japanese (Romanized) / Japan: Billy
• Japanese (TL) / Japan: Billy

Billy is a fan of Electric-type Pokémon and a circus performer. The top stars of the circus are Harmony, who likes Fire-type Pokémon, and Billy, who likes Electric-type Pokémon. He does breathtaking performances with his Pokémon. The two had been performing during practice but the truth is that they were rivals because they thought that their Pokémon type were the best.

After a disagreement with Harmony, they dropped their evolution stones which got mixed up and their partner Pokémon evolved into the wrong types. Billy's Eevee (Toril) was supposed to evolve into a Jolteon during the performance but during practice, Harmony's Fire Stone touched it and it evolved into Billy's Flareon (Toril). He was sad after it evolved because it couldn't use Electric-type moves with the rest of the team for their performance.

With some help from Chloe's Eevee and it showing its Copycat move, they got the idea to use their moves from the opposite side trapezes for Billy's Flareon (Toril) and Harmony's Jolteon (Bernice) at the start of the performance so that their type mismatch now seemed to be part of the show. Despite his initial disappointment with the Fire Stone evolving his Eevee into a Flareon, he began to see the appeal for Fire type Pokémon. As thanks for helping out, he gave Chloe Cerise a Thunder Stone.