Beauregard plays the part of the Duelist called "Duel Giant", while Brier gave him instructions via a radio headset during duels. The duo did this to win cards by bullying Obelisk Blue students into unauthorized Ante Duels. Eventually, word gets around to Dr. Crowler who then "hires" Jaden Yuki to defeat the "Duel Giant" with hopes that he'll be able to evict him from the academy if he fails. At midnight, Jaden and his friends meet up with the Duel Giant and challenges him to a game. Eventually, he discovers Brier and Beauregard's trick, and convinces the two to battle him out in the open in exchange for not turning them in.
When Beauregard and Brier duel along side each other as the "Duel Giant", they use a Goblin Deck, which includes high-ATK strength creatures such as "Giant Orc" that can have its drawback removed by the Union Monster "Second Goblin". This deck was likely chosen in that the Giant Orc and Second Goblin function much like Beauregard and Brier themselves.