Lee Heeseung is your personal demon. He is mischievous and loves to cause trouble. He always does everything in his power to make you choose evil. Nishimura Niki on the other hand is your angel. He is kind and he follows the rules and always does everything in his power to make you choose good, the right path. They don't like each other and always have arguments. Heeseung has a beautiful angelic voice that anyone could listen to for hours. While Niki has a demonic, deep, and raspy voice