The spinoff follows Ryuunosuke Akutagawa, who vows revenge on a man dressed in black in order to rescue his sister. However, as he is about... more>> to starve to death, a man from the Armed Detective Agency appears. <<less

The manga is based on the spinoff light novel of the same title and explores the past of the characters Osamu Dazai and Chuuya Nakahara.

The story is set after the "Arahabaki Incident," and one year after Chuuya Nakahara joined the Port Mafia. A detective from Europe named Adam appears in front of Chuuya, with the aim of protecting Chuuya from Paul Verlaine, also known as the king of assassins. Paul claims to be Chuuya's old brother, and he vows to murder everyone Chuuya cares about.... more>>

Based on LN Vol 8. <<less