Ken Oyanagi (大柳 賢 Oyanagi Ken), originally referred to as Rock-Paper-Scissors Kid (ジャンケン小僧 Janken-kozō), is a minor antagonist appearing in Diamond is Unbreakable.
Ken is an ordinary child made into a Stand user by Yoshihiro Kiraand prompted into challenging Rohan Kishibe in a game of rock-paper-scissors in which the latter must gamble his own Stand. Ken's ability is named Boy II Man.