From Bulbapedia, the community-driven Pokémon encyclopedia.
Joshua (Japanese: トシキ Toshiki) is a Pokémon Coordinator who appeared in the anime. He appeared in Mean With Envy and Pacifidlog Jam.
Joshua was training for the Pacifidlog Town Pokémon Contest with his girlfriend, Erica. Her dream was for her and Joshua to be the first couple to win a Pokémon Contest together. However, Joshua felt that Erica was focusing too hard on the Contest and would try to get away from her as often as he could.
When May arrived in town for the Contest, Joshua began talking to her. Erica, in a fit of jealousy, believed she was trying to steal Joshua away from her.
During the Contest, May faced Joshua in the first round after the appeals stage. Although Erica wanted him to defeat May, Joshua lost to her. Erica was angry at May, but then Joshua approached her and told her that he and May were not romantically seeing each other, but instead that Joshua just wanted some time away from Erica.
After May won the Contest, Erica apologized to her, saying she had no reason to be jealous. May accepted the apology, and as the young Coordinator headed off to the Grand Festival, Erica and Joshua promised to cheer for her.
Both had a small cameo during the Hoenn Grand Festival watching it on TV.