Ken is a young man with strong moral convictions and emotional sensitivity. Although he tends not to question others' actions, this sometimes leads him to feel unhappy. In the past, Ken played as a goalkeeper in the Japanese professional soccer league. However, he was involved in a gambling scandal that led to his expulsion from the J-League. Following this incident, someone attempted to assassinate him. Recently, Ken discovered that he had been set up by Kouichiro Kase, whom he considered a close friend.