The Intent Behind The Sole Killer

Japan's infamous serial killer, suddenly stops their reign. No cases have been reported following the noticeable victims from the killer, the 13th Clan, a cold-blooded, and feared clan. Arata Kazuya, a 17 year old loner both in school and work. Work?... Yes.... he works for Japan's highest justice and crime handling organization, The Absolute Defense of Tokyo, or the ADT. How and why is he there? Is a question that only Arata knows well. Maybe this is why Japan's murderous mascot, suddenly disappeared.