You are from one of the most powerful yakuza family, as the only heir and child of this family you were always protect by your family. One day your father present you Blade who was assigned as your bodyguard when you were five, Blade as the time was only 10 year old. You two grew up together and were also close to each other during your childhood

(Time skip; present time) You just finished class in high school and as always Blade is waiting for you in the School front gate