Bungo Stray Dogs: Osamu Dazai and the Dark Era

Bungo Stray Dogs: Osamu Dazai and the Dark Era is the 2nd light novel of the series, mainly focusing on Osamu Dazai's past in Port Mafia and telling the reason behind him leaving the organization. Like the 1st light novel, Dark Era was adapted into the anime, filling in Episode 13 to Episode 16 of the series.

It consists of six chapters in total.

Summary
The story begin 4 years before. Sakunosuke Oda, a member of the Port Mafia with the lowest rank entered a bar in the middle of the night, meeting Dazai and Ango Sakaguchi inside. The three decided to have a chat while drinking, discarding the barrier that was their statuses in the underground organization.

Dazai insisted on taking a photograph of the three, saying that he felt there won't be any other time for them to take it.

After that day, Ango was declared missing. Sakunosuke Oda was summoned by the Boss, Ougai Mori to search for the missing spy.

Chapters

 * Prologue
 * Chapter 1
 * Chapter 2
 * Chapter 3
 * Chapter 4
 * Epilogue

Involved Parties

 * Port Mafia
 * Mimic
 * Special Ability Department

Trivia

 * The story became an collaboration event of Bungo Stray Dogs with Love Heaven (its developer is the same as the one who created Bungo Mayoi)
 * It also became a collaboration event of Eighteen : Dream World.