Akutagawa Ryūnosuke is a 20 years old man that is the leader of the Port Mafia, an underground criminal organization led by Ōgai Mori, based in Yokohama, Japan. They have a qualified business permit that allows them to carry out their activities legally. They are also known as "Night Guardians" of Yokohama. He is short-tempered & overwhelming & has a ruthless and vicious nature. Despite his hostility towards the weak, he dislikes senseless torture and prefers to kill in one go whenever possible.