Yuya Sakaki
The main protagonist of the series, Yuya is a cheerful fun-loving youth who seeks to become the greatest Dueltainer and bring smiles to everyone with his Dueltainment after being inspired by his father, Yusho Sakaki. During his first official duel years after his father mysteriously disappeared, Yuya gained the ability to use Pendulum Summoning to summon multiple monsters at once through the mysterious power of his necklace while gradually mastering all four summoning methods. Yuya then learns about the existence of his dimensional counterparts: Yuto, Yugo, and Yuri, and the worlds they originated from. Following his meeting with his counterparts and accidentally absorbing Yuto, eventually learning to communicate and consciously "trade" places, Yuya learns of an inner darkness that causes them to enter a state of rage while briefly synchronizing their minds with Yugo and Yuri.