No Longer Human

Nullify all abilities, but only through touch.

No Longer Human is the supernatural ability wielded by Osamu Dazai within the Armed Detective Agency. While the narrative establishes Dazai's pivotal role in recruiting Atsushi Nakajima and countering threats like Fyodor Dostoevsky, it clarifies that he did not use his ability for recruitment; instead, he found Atsushi on a suicide attempt and offered him employment without nullifying any powers. The ability serves as a definitive tool against the Port Mafia and the Decay of the Angel by rendering supernatural threats inert upon touch.

Quick Facts

Wielder: Osamu Dazai
Affiliation: Armed Detective Agency (formerly Port Mafia)

Lore & Background

The text explicitly details that 'No Longer Human' functions by nullifying other abilities through physical contact. This mechanic is central to Dazai's strategy in resolving conflicts involving the Port Mafia and Fyodor Dostoevsky's groups, including the eventual arrest of Dostoevsky alongside Atsushi and Akutagawa. Despite his past imprisonment, Dazai remains a central operative, forming alliances with former enemies like Francis Scott Key Fitzgerald to counter the Hunting Dogs and the Decay of the Angel.

Reader's Guide

Dazai's design contrasts with Ryunosuke Akutagawa and that he acts as a 'sage' figure to Atsushi's hero role. While it states that characters are named after authors whose powers are based on their books, the specific rules governing Dazai's ability are not detailed in this source.

Did You Know?

Osamu Dazai serves as a 'sage' figure in the story, acting similarly to Merlin to King Arthur for the protagonist Atsushi Nakajima.
Sango Harukawa, the illustrator, always wanted to draw a white tiger, which influenced the design of Atsushi Nakajima's ability.

Origins and Creative Inspiration

The character of Osamu Dazai was created by writer Kafka Asagiri, who found inspiration in reading the author's book No Longer Human. Asagiri expressed that he felt a connection to Dazai's expression of embarrassment involving his entire life, which motivated him to create a version of the character that would stand out among readers. Following the selection of Atsushi Nakajima as the main character, Asagiri needed a third character to act as an equal to Dazai, leading to the creation of Kunikida. The writer described the process of developing these characters and their backgrounds as 'mysterious,' noting that he could complete background drafts in two to four days. Sango Harukawa provided designs that helped Asagiri create stories more easily, with specific revisions made to ensure Dazai's design heavily contrasted with Akutagawa.

Narrative Arc and Supernatural Conflict

The story follows Atsushi Nakajima, a weretiger who joins the Armed Detective Agency under Osamu Dazai. The narrative expands as they face Ryūnosuke Akutagawa of the Port Mafia and Francis Scott Key Fitzgerald of the Guild. A major conflict arises when Fyodor Dostoevsky uses a virus ability user to clash the detectives and mafia, leading to Dazai arresting him. Later, pages of 'The Book' are found by Dostoevsky's group, the Decay of the Angel, framing the Agency. As the situation escalates with the government's Hunting Dogs, Dazai is imprisoned but later forms an alliance with Fitzgerald and the mafia. The climax involves a confrontation where Atsushi defeats a god-like entity created from Fyodor's abilities, after which the Detective Agency is forced to close.

Adaptations and Media Expansion

The manga began serialization in Kadokawa Shoten's Young Ace on December 4, 2012. An anime television series adaptation produced by Bones aired in two parts in 2016, with a third season in 2019, a fourth in early 2023, and a fifth from July to September 2023. A film titled Bungo Stray Dogs: Dead Apple was released in March 2018. Ten light novels had been published as of 2025. A spin-off series, Bungo Stray Dogs Wan!, aired from January to March 2021, with a second season scheduled for July 2026. Additionally, a live-action film, Bungo Stray Dogs The Movie: Beast, was released in Japan in January 2022.

Character Dynamics and Thematic Depth

Osamu Dazai serves as the 'sage' to Atsushi Nakajima's hero role, contrasting sharply with Ryūnosuke Akutagawa. The author Kafka Asagiri designed Dazai based on the emotional core found in No Longer Human, aiming for a character that readers could connect with due to his complex nature. The narrative explores themes of redemption through characters like Kyōka Izumi, who transitions from an assassin for the Port Mafia to Atsushi's partner. Villains such as Francis Scott Key Fitzgerald are written to be relatable despite their destructive actions, driven by personal desires like protecting family. The story questions the lines between justice and terrorism, particularly with the arrival of the Decay of Angels and Hunting Dogs.