Port Mafia Arc

The Armed Detective Agency vs Port Mafia Arc is the first story arc in Bungo Stray Dogs.

Serving as the introductory arc, it showcases the protagonist, Atsushi Nakajima, as he adapts to live with his ability and meets both the Armed Detective Agency and Port Mafia, becoming the epicenter of their latest conflict.

Story Impact

 * Atsushi Nakajima discovers his ability and joins the Agency.
 * The Armed Detective Agency is introduced.
 * Port Mafia is introduced.
 * Osamu Dazai's past occupation as a member of the Port Mafia is revealed.
 * Atsushi Nakajima and Ryunosuke Akutagawa develop their rivalry.
 * The rivalry between Osamu Dazai and Chūya Nakahara is introduced.
 * Kyōka Izumi defects from Port Mafia.

Trivia

 * As the Azure King conflict is canon to Osamu Dazai and the Entrance Exam, its anime appearance, and by extension, Atsushi's involvement, is non-canon to the source material.