Port Mafia Arc

The Armed Detective Agency vs Port Mafia Arc is the first arc of 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.

Impact

 * Atsushi Nakajima discovers his ability.
 * Armed Detective Agency was introduced.
 * Port Mafia was introduced.
 * Osamu Dazai's past occupation revealed.
 * Atsushi Nakajima and Ryunosuke Akutagawa develop their rivalry.
 * Osamu Dazai and Chūya Nakahara's rivalry 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.