The Duel Giant ("Giant Duelist of the Dark Night" in the Japanese version) was the combined persona used by Brier and Beauregard when dueling along side each other. The Giant was responsible for several incidents of theft by way of Ante Duel during Jaden's first year at Duel Academia, and was ultimately brought down by Jaden.
To create the Giant, Beauregard played the part of the Duelist, disguised behind an enormous cloak made of male Obelisk Blue uniforms and a pair of reflective sunglasses. Meanwhile Brier fed him instructions via a radio headset from a hiding spot nearby, taking advantage of his small size to hide under the cover of darkness. The "Giant" persona helped Brier and Beauregard overcome their respective difficulties, taking advantage of their untapped potential. When Beauregard Dueled in his place, Brier could show all his potential despite his stage fright. Plus, as they operated under the cover of darkness, Beauregard could duel without other people being afraid of his large size. The two made use of the "Duel Giant" persona to take revenge on Obelisk Blue students who bullied the pair, terrorizing the bullies into Duels using the forbidden Ante rule. However, their string of card thefts eventually caught the attention of Dr. Crowler, who sent Jaden Yuki to defeat the Giant. During their duel, a stray attack by "Elemental HERO Rampart Blaster" threw off Beauregard's costume, exposing the duo's trick. Ultimately, Jaden convinced the pair to battle him out in the open in exchange for not turning them in, and the pair returned the stolen cards.
As the Duel Giant, Brier and Beauregard 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". The deck reflected the relationship between Beauregard and Brier themselves, a small brainy character and big brawny one covering one another's weaknesses.