Lua is the older fraternal twin brother of Luna, and together they live in the Tops district of New Domino City. Their parents are frequently away on business trips, leaving the twins to largely fend for themselves. Lua is a young boy full of boundless energy, with a lively, loud, and blundering personality. He often serves as the comic relief among his companions, cracking jokes and acting like a goofball. Despite this carefree exterior, he becomes serious when the situation demands it, and he rarely hesitates to rush headfirst into dangerous duels, displaying a complete lack of fear. Lua idolizes Jack Atlas above all others and aspires to be just like him when he grows up; he also looks up to Yusei Fudo as a hero and a source of inspiration. His deepest motivation is the protection of his sister Luna. He loves her with all his heart and is willing to do absolutely anything to keep her safe, even though he sometimes doubts his own skill and feels he is not of much use. Their bond is strong, and despite their occasional bickering, they care for each other immensely. Lua primarily uses a Morphtronic deck, which features monsters that change their effects depending on their battle position, and his signature monster is Power Tool Dragon. He rides a tandem D-Wheel with Luna seated behind him. Over the course of the story, Lua grows significantly as a duelist. He is initially portrayed as less skilled than his sister, but he continues to improve and achieves notable victories. His most pivotal development occurs during a life-or-death duel against Aporia. On the brink of death, Lua's overwhelming desire to protect Luna awakens a dormant power within him, and he becomes the sixth and final Signer, bearing the Heart mark of the Crimson Dragon. This awakening grants him access to the true form of his dragon, Life Stream Dragon, a Synchro Tuner monster that eventually aids Yusei in summoning one of his most powerful monsters.