Sadie

Sadie, known in Japan as Seiko, is a young lady who works in Ms. Dorothy's card shop. Her personality is generally cheerful and unassuming. Her name is never given in the English version of the anime, but she is named in the video games. The Japanese credits of episode 4 do name her. She claims to have little knowledge of how to Duel, but can be faced as a opponent in the GX Tag Force series, in which she is usually a tough opponent.