The Factions
Five major power blocs. Five moral philosophies. One city that barely holds them apart.
Faction One
The Armed Detective Agency
A band of detectives who specialize in cases too dangerous for the military or police — ability users who stand at the edge of twilight, protecting Yokohama from threats no one else can handle.
If any faction represents light in BSD, it’s the ADA. That said, “light” in this series is always complicated. Their leader Fukuzawa built the Agency partly as a safe harbor for ability users who had nowhere else to go — and many of them didn’t. Dazai walked in from the mafia. Kyouka walked in from assassination.
They are heroes. Mostly.
Key Members
Atsushi Nakajima Protagonist
Power: Beast Beneath the Moonlight
Transforms into a massive white tiger. Orphaned, abandoned, and still learning he deserves to exist. The heart of the entire series.
Osamu Dazai Former Port Mafia Executive
Power: No Longer Human
Nullifies any ability by touch. The fan favorite. His goofy suicidal persona is a flawless mask over the most calculating mind in Yokohama.
Ranpo Edogawa The Genius
Power: Ultra-Deduction (not an ability — just his brain)
The greatest detective in the world, who cannot function at a grocery store without help. He has no supernatural ability. He’s just that smart.
Yosano Akiko The Doctor
Power: Thou Shalt Not Die
Heals any wound — but only near-fatal ones. She must bring patients to the edge of death before she can save them. The team’s medic is the most disturbing person at the table.
Fukuzawa Yukichi Director
Power: All Men Are Equal
Grants his subordinates full control over their own abilities. The quiet, cat-loving patriarch whose sword can be drawn at the speed of sound. The reason the ADA functions at all.
Key Members
Ryunosuke Akutagawa The Enforcer
Power: Rashōmon
His black coat transforms into a beast that tears through anything — even space itself. Raised in slums, trained by Dazai’s cruelty, desperate for approval he may never receive. The most tragic figure in the series.
Chuuya Nakahara Dazai’s Other Half
Power: Upon the Tainted Sorrow
Manipulates gravity itself. In his awakened Corruption state he becomes an unstoppable singularity — but it will kill him if Dazai doesn’t cancel it. The two hate each other and are completely dependent on each other. BSD fans have been debating this for a decade.
Mori Ougai Boss
Power: Vita Sexualis
Summons Elise — a weaponized little girl avatar. Charming, dangerous, and entirely untrustworthy. He became boss by killing the previous one. He is always weighing pros and cons, but always for the Mafia’s benefit, never anyone else’s.
Kyouka Izumi Former Assassin
Power: Demon Snow
Her ability summons a lethal demon — but she couldn’t control it. Someone else held the trigger. One of the most heartbreaking setups in the series. She eventually finds her way to the ADA.
Faction Two
The Port Mafia
The wardens of Yokohama’s night. Ruthless and disciplined, the Port Mafia controls the city’s underworld — its politics, its economy, its shadows. They are not simple villains.
BSD eventually forces the ADA and the Mafia to work together. When it does, you realize the Mafia’s members aren’t monsters — they’re people who grew up in a world that gave them no better options. Every one of them carries that weight.
The real literary authors behind these characters all shared one thing: they sought to push against the established order. Controversial, subversive, ahead of their time.
Faction Three
The Guild
A secret society of North American ability users who descend on Yokohama with enormous wealth and one goal: acquire a mythical book that can rewrite reality itself. They are named after American and Western literary giants.
Their leader, F. Scott Fitzgerald, literally burns money to grow stronger. H.P. Lovecraft shows up and turns out to be something genuinely eldritch — not fully human at all. Mark Twain uses Tom Sawyer and Huck Finn as twin sniper dolls. Edgar Allan Poe traps enemies inside his detective novels.
After their defeat, the Guild fractures — some members become allies, others grow more dangerous. Fitzgerald himself earns one of the series’ most interesting redemption arcs.
F. Scott Fitzgerald
The Great Fitzgerald
Spends money to gain strength. The richer he burns, the more unstoppable he becomes.
H.P. Lovecraft
The Great Old One
Not really human. After being defeated he walks into the ocean to sleep. Nobody stops him.
Edgar Allan Poe
Unfinished
Traps enemies inside his novels — escape requires solving the mystery. Becomes genuinely fond of Ranpo.
John Steinbeck
The Grapes of Wrath
Grows massive grape vines from seeds in his own bloodstream. Relaxed until he isn’t.
Mark Twain
The Adventures of Tom Sawyer
Uses Tom Sawyer and Huck Finn as twin sniper paper dolls. Treats combat like an adventure.
Lucy M. Montgomery
Anne of Abyssal Red
Traps people inside an infinite house. Initially hostile — eventually an unexpected ally.
Factions Four & Five
The Rats in the House of the Dead & The Decay of the Angel
Fyodor Dostoevsky — The Rats
The main antagonist of BSD Part 1. A criminal mastermind with absolute stillness concealing a will to reshape the world. His goal: find the reality-altering Book and use it to eliminate all ability users, whom he considers sinful — using deeply sinful methods to do so.
His ability, Crime and Punishment, allows him to cheat death itself — anyone who kills him becomes his vessel. He views every single person around him — allies, subordinates, enemies — as instruments to be discarded when their role is complete.
He is Dazai’s intellectual equal and archenemy. Two genius-level minds playing chess with everyone else as pieces.
The Decay of the Angel — False Flag Terrorism
A terrorist group constructed by Fyodor to destroy the ADA from the outside while he works from within. Their members include Nikolai Gogol — a circus-ringmaster-dressed agent of chaos who pretends to be a psychotic killer while being completely sane, and feels genuine guilt for every murder.
And Bram Stoker — yes, that Bram Stoker — whose ability infects others and turns them into vampires he controls, spreading with terrifying speed.
Their entire operation was Fyodor’s puppet show. None of them knew it until it was too late.