The owner of the Green Drugstore, Kakei is the one who sends the two boys out on missions, usually without telling them everything first. He seems to know exactly how things will turn out due to his power of precognition, however it has been noted that this power cannot be used on someone more powerful than himself, as in the case of his failures to find Tsukiko for Rikuo.
Kakei is a very beautiful person and has a gentle, kindly air about him. However, he is also very mysterious, and his expression often changes quickly from gentle and kindly to eerie and perhaps even dangerous. He is also noted to have a cruel, and even sadistic side to his nature, although this side of his personality is mostly actualized in almost-subtle teasing.
It turns out that the reason he opened the Drugstore is in order to protect Kazahaya and everyone he cares about.