Port Mafia

The Port Mafia (ポートマフィア,) is an underground criminal organization run by Ōgai Mori, based in Yokohama, Japan. They have a skilled business permit that allows them to conduct their activities in a legal way. They are also known as Yokohama's "Night Wardens".

Influence
According to Ichiyō Higuchi, the Mafia has dozens of enterprises under their control. It also exceeds politics and as well as economics and its influence is found in many sections of Yokohama. Those who defy them will only burn and not survive.

It is noted that the Port Mafia serves as vendors for organs, chemical weapons, and criminal personnel. They deal entirely in illegal products for underhanded organizations, and is considered the general trading company of the criminal underworld. They oversee countless shady operations and form connections with criminal organizations across the globe.

While the Mafia has vast reach, Osamu Dazai mentioned prior to acquiring a skilled business permit that the Port Mafia did not dabble in the drug industry. He further noted that the Special Division for Unusual Powers, narcotics bureau, and the military police's anti-organization surveillance committee waited for the Mafia to make such a blunder, making the drug industry more trouble than its worth.

Structure
The Port Mafia divides its power largely between its boss and his five executives, who answer solely to him and lead their own factions within the mafia. Originally, four identified executive positions were filled, including Dazai, Chūya Nakahara, Byakuren, and Ace

However, it was later revealed that Paul Verlaine is also an Executive. Due to him never leaving the underground Mafia shelter, he is never seen in meetings with his fellow Executives. With Dazai's defection and Ace's death, Kōyō, Chūya, and Verlaine remain as the three surviving executives, but Mori keeps Dazai's position reserved solely for him, somehow waiting for him to return. Training of assassins is largely handled by Paul Verlaine, who has trained both Gin and Kyoka who both became promising assassins in a short period of time. In Kyoka’s case, killing 35 people in a matter of 6 months and in Gin's, quickly rising the ranks to be part of the Black Lizard unit at her young age.

Kōyō leads a major interrogation unit skilled in torture. Another major faction of the Port Mafia is its guerilla attack force, led by Ryunosuke Akutagawa, having succeeded his former mentor Dazai. Working alongside him is Higuchi, who largely acts as his right hand.

The Port Mafia also has an intelligence unit, largely maintained by Ango Sakaguchi in the past.

A large number of mafiosi are low-ranked, such as Sakunosuke Oda. Such ranks deal with many lowly and menial tasks such as managing security for paying stores and settling disputes between paid allies and their interpersonal conflicts or even being used as expendable assets as what Mori stated.

Flags
The Flags are a group of young mafiosi aged 25 years old and below. The group originally don't have a name until  Chūya suggested to name the group as "Flags". Its members include Lippmann, Piano Man, Albatross, Doc and  Ice Man. Each of the members have its own responsbility in the mafia.