
Hayato Adachi was a Japanese real estate businessman who lived in Tokyo during the 2010s. He was classmates with Masaharu Kaito in high school, and the two became fast friends due to their shared delinquency. Adachi went on to become a successful businessman as the president and director of Adachi Estate, using shady methods such as violence and blackmail to acquire properties. In 2018, he attempted to dupe Kaito into working for him as muscle, and Kaito agreed, although he secretly intended to discover for himself if the rumors about Adachi were true. When Kaito's friend Takayuki Yagami revealed that Adachi planned to use the planned assault of an innocent girl as blackmail material, thus uncovering Adachi's crude nature, Kaito deserted Adachi and helped Yagami beat him and his thugs to punish them.