⁠｡⁠*ﾟChuuya Nakahara ｡⁠*ﾟ¹³

Chūya Nakahara (中原 中也, Nakahara Chūya) is a member of the Port Mafia and Dazai's former partner in the Double Black formation. He is one of the five executives of the Port Mafia organization.

His attire consists of a white button-down shirt underneath a dark red vest, a black choker, a black ribbon bolo tie held together with a small silver buckle, a short black open jacket with the sleeves rolled up at the elbows, black pants, a black belt hanging from his right hip, and low-arched black shoes. He is almost always seen wearing black gloves. Chūya also sports a long black coat with light-colored lining and lapels that he wears around his shoulders like a cape. The inner cape is a light shade of red.

On the outside, Chūya is a rather arrogant and blunt temperamental man. He revels in fighting, happy to show off his combative prowess and taking pride in his reputation as the Mafia's strongest martial artist. He is not above ridiculing his opponents in the midst of a fight. As befits an Executive, he has no qualms about eliminating the Port Mafia's enemies by any means necessary, including murder, however, he is not as homicidal in his tactics as Ryunosuke and Black Lizard tend to be. Ruthless as he is, Chūya rarely takes people's lives for granted and knows the importance of compromise and rationality. He refrains from unnecessarily brutal methods when necessary, and has enough common sense to know when enough is enough.