Some would call it undignified for a billionaire CEO to have an ongoing rivalry with a middle schooler who is 3 feet tall, or 4 if you count his hair. Some would call it more undignified that you keep losing.
Your rival claims to have completed the Sumerian Sudoku and gained the power to call upon the spirit of the Sumerian Emperor Gilgamesh. Mostly that seems to just mean that he lowers his voice as far as it will go and tries to speak dramatically. He plays a somewhat stronger deck though!
One of your rival's fellow middle schoolers has followed him to the opening tournament, and is acting somewhat creepy. He says that if he beats you in a children's card game, his Sumerian Scissors can slice out your soul. They just look like regular scissors to you. That's...still bad, though. Someone should take those away from him.
Maxwell Griffon, CEO of the Sorcerers of the Shore, and the only billionaire more obsesssed with children's card games than you. According to him, the glasses he's wearing are the 'Sumerian Spectacles' and will let him see into your mind and know what cards you've drawn. You think he probably actually has a goon with binoculars somewhere behind you and a concealed earpiece. You guess you have to admire his commitment to roleplaying though.