Ryunosuke Akutagawa is a Port Mafia member marked by a pale complexion, frail build, and persistent cough stemming from childhood lung damage in Yokohama's slums. His appearance features short black hair with distinctive white-tipped bangs framing his chin, sharp gray eyes, and a signature black coat worn over a white ruffled shirt and jabot—a garment whose name escapes him. This coat serves as the essential medium for his ability, Rashōmon, though he adopts simpler attire for outings with his sister Gin or a modified version after a vampire transformation alters his eyes and adds vein-like markings. Akutagawa rigidly adheres to a "survival of the fittest" philosophy, deeming weakness worthy of death. He executes Port Mafia orders ruthlessly, eliminating targets—civilians included—without hesitation, preferring efficient kills over gratuitous torture. While generally detached, he exhibits volatile anger, particularly when his competence is doubted or when discussing his former mentor, Osamu Dazai. His loyalty to the mafia hierarchy coexists with deep disdain for Dazai's defection, which he views as a betrayal of the organization's principles. Orphaned alongside Gin in the slums, a pivotal moment occurred at fourteen when criminals murdered his companions after he overheard Port Mafia dealings. Seeking vengeance, he found the perpetrators already dead by Dazai's command. Dazai then offered him a choice: become his subordinate or receive financial security. Akutagawa chose the mafia, driven by rage and a burgeoning respect for Dazai, shaping his relentless pursuit of Dazai's approval. This pursuit intensified after Dazai's departure and his subsequent praise of Sakunosuke Oda, a non-killer Akutagawa deemed inferior. His ability, Rashōmon, manifests as a shadow-like beast emerging from his clothing, capable of consuming matter—even space—to form defensive barriers or launch attacks. Named techniques include: - **Agito (Jaws)**: Biting constructs. - **Murakumo (Swarm)**: Claw-like appendages. - **Sawarabi (Budding Bracken)**: Ground-erupting spikes. - **Higanzakura (Early Blooming Cherry Blossom)**: Explosive impaling tendrils. - **Spider Thread**: Razor-sharp nets. - **Demonic Armor**: Defensive encasement. The dependency of Rashōmon on clothing as a medium fuels his aversion to bathing due to perceived vulnerability. His primary rivalry targets Atsushi Nakajima, Dazai's current protégé, whom he initially derides as weak and hypocritical for seeking acceptance. Akutagawa's contempt stems from envy of Atsushi's innate strength, supportive allies, and Dazai's favor—advantages he lacked despite rigorous training. Witnessing Atsushi's resolve during the orphanage director's death, however, prompts reluctant respect; Akutagawa spares him and later cooperates against mutual threats like Fitzgerald and Goncharov. Their dynamic evolves into a contentious alliance during conflicts with the Guild and Decay of the Angel. Despite his brutality, Akutagawa demonstrates sporadic loyalty: assisting Gin without complaint, apologizing to subordinate Higuchi after her rescue, and ultimately sacrificing himself against Fukuchi to enable Atsushi's escape. In his final act—using Rashōmon to breach Fukuchi's defenses while fatally wounded—he underscores his enduring fixation on validation, declaring actions over words define his legacy. Posthumously, his transformation into a vampire under Bram Stoker's influence positions him as an antagonist in later arcs, his core drive for purpose unresolved.