• English / United States: Sean
• Japanese / Japan: セイン
• Japanese (Romanized) / Japan: Thane
• Japanese (Trans) / Japan: Thane

Sean is an aspiring Pokémon Trainer who's father has a bunch of Pokémon. Sean ended up borrowing his fathers Pokémon so that he and his friends could have Pokémon battles together. His family had traveled to Yamabuki City in the Kanto region and he saw a Pikachu while he was there so he was able to correctly identify Ash Ketchum's Pikachu. His personality is a bit of a spoiled brat and a know-it-all but he easily controlled when he relents his position to appease his friends.

Battle against Glenn

In the first battle against Glenn, Glenn pushed Sean's Father's Patrat and Sean's Father's Blitzle to the point of exhaustion before they finally decided to stop the battle. Glenn then told Sean to get some more of his fathers Pokémon so they could continue battling. Not wanting to disappoint Glenn or make him mad, Sean went to go get them and Glenn went to go look for Mick who had shown them Pikachu earlier and had initially wanted to battle.

Double Battle against Mick

After Sean's Father's Blitzle and Sean's Father's Patrat were too tired to battle, Sean went back to his dad and borrowed Sean's Father's Scolipede and Sean's Father's Seismitoad so he and his friends could continue battling. Glenn commanded both of the Pokémon in a double battle against Pikachu and Ash's Krokorok even though Sean was supposed to command one of the Pokémon.

Sean attempted to help out by giving Glenn advice by specifically telling him to match up Sean's Father's Seismitoad against Pikachu because of the type advantage but Glenn wouldn't take the advice. The inexperience of Glenn and his unwillingness to accept advice proved to be the reasons that Sean's Father's Scolipede and Sean's Father's Seismitoad lost the battle.

Mick won the double battle and he was quite moved to have participated in a simulated Pokémon battle. He fought against Glenn the best that he could but Glenn got a bit upset that he lost. Ash Ketchum made Glenn apologize and the two of them continued to be friends. Glenn and his friends hoped to have another Pokémon battle someday against each other. After watching the Pikachu and Ash's Krokorok battle each other, Sean was even more moved to become a Pokémon Trainer someday.