Dragon's Head Conflict

Dragon's Head Conflict (龍頭抗争, Ryū'zu Kōsō) is an underground conflict in Yokohama between various underground organizations. It lasted for 88 days and is labelled as the darkest conflict in Yokohama's history.

Background
The conflict started six years ago. An ability user died, leaving behind their humongous amount of fortune. Various criminal organizations began to move, battling to claim it. The incident turned Yokohama into a bloody battlefield that lasted for 88 days.

Casualties involving the mafia, criminals and innocent civilians. In this conflict, Sakunosuke Oda rescued the five orphans who lost their parents to the crossfire. Sakura is the first orphan he finds and saves.

Tatsuhiko Shibusawa was involved due to the Japanese Government's intervention. They intended to have him settle the dispute, but instead he exacerbated it.

After discovering his comrades committed suicide, Chūya ultimately ended the conflict using Corruption. The Port Mafia emerged victorious thanks to Chūya Nakahara and Osamu Dazai, marking their new nickname as Twin Dark Black (双黒, Soukoku), the "most devastating rivalry".

Summary
Sakunosuke Oda enters a ransacked jewellery store, one used by GSS as more or less a shell company. His intention is to investigate who robbed the store, but he meets Tatsuhiko Shibusawa. Shibusawa mentions a corpse in the store, and the method of murder shocks Odasaku. He deduces they were killed by the culprit but is still stunned at how one person could kill so many powerful ability users. Shibusawa argues it's not shocking, as it's a time of war in Yokohama, and ability users die all the same.

Odasaku asks Shibusawa if this is his first time in Yokohama, as so many deaths of powerful ability users, and attacking a group like GSS, is unheard of. Shibusawa dismisses it as a foolish criminal's attack. Odasaku asks about a rumour regarding a “White Dragon”, but Shibusawa says it's not his place to judge the culprit and plans to take his leave. Just before he leaves, he reveals the culprit's “true intention”. A bored individual, the culprit idly takes anything that catches his eye. After this, he leaves Odasaku, saying he'd like to speak to him again if he's alive.

After he leaves, Osamu Dazai arrives, asking if Odasaku is okay. He explains he arrived after receiving some information and asks Odasaku if a man with long white hair appeared. Odasaku confirms this, and Dazai says its good Odasaku is alive after coming face to face with the White Dragon himself, a man trying to take over the conflicts.

70 days into the conflict. Chūya wakes Dazai up from sleeping in his office, irritated by Dazai's nonchalance over the intense conflict. Summoned by the Port Mafia Boss himself, the two must attend a meeting alongside the other higher-ups.

Dazai, knowing the happenings outside, continues to tell Chūya the details of the war; the casualties caused by the overseas organization - 'Strain', the death of 'Takasekai's leader which lead to its collapse, as well as the casualties suffered by the other organizations. Dazai tells Chūya to leave the dispute to Mori, as there lies a more concerning activity.

He shows Chūya a photograph of a corpse, later revealed as one of the Mafia's Executives, codenamed 'Colonel'. His death creates an empty seat in the Five Executives. Chūya doubts the 'Colonel' could die so easily, mentioning that the deceased man is one of the strongest Ability-user in Mafia's ranks. Dazai tells him the killer is the 'White Dragon', however, not even Dazai knows the White Dragon's ability.

While Chūya says he will kill the culprit himself, Dazai insists both of them should be more concerned about the Executive Candidacy. Chūya dismisses the statement, leaving Dazai alone.

Later, Shibusawa reappears, noting the streets are more populated than normal considering the ongoing war. He approaches a florist, asking her for a bouquet of white flowers, but the woman reveals a gun. The woman, alongside all the other 'citizens', is part of a faction Dazai leads. Dazai confronts Shibusawa himself, bluntly telling him he won't hesitate in killing him, and that, no matter how powerful the ability, a "one-man army" stands no chance against a juggernaut faction of ability users like the Port Mafia.

This concept interests Shibusawa, who asks Dazai if "power in numbers" is why Dazai joined the Port Mafia, to which Dazai confirms. Their conversation continues, and in the end, Dazai states that while he can let go of the death of 'Colonel', he is not kind enough to leave Shibusawa alive. Shibusawa approves of Dazai's resolve, urging him and the Port Mafia to show no remorse. He states the conflict will not end until he is defeated. Dazai argues it will only end after everyone dies, and claims to know a way to end everything. To which, Shibusawa suggests "more conflict".

Shibusawa compares the Dragon's Head Conflict to a conflagration - a large, destructive fire - and the only way to end it is to extinguish its flames with an even larger, greater explosion. A massive explosion goes off, much to Dazai's (rare) shock. Shibusawa explains he's arranged a war between the Port Mafia and all the opposing organisations combined and intends to destroy their headquarters.

Dazai cannot believe Shibusawa arrived here, prepared to die, but Shibusawa informs him he made two miscalculations. An array of different abilities attack, slaughtering the gunmen. Shibusawa confirms Dazai's claim: that the power of an organisation is incredible, as he found his way into one out of sheer boredom. Another assault hails down on the Port Mafia's headquarters.
 * 1) Shibusawa knew of the ambush.
 * 2) Assuming Shibusawa belongs to no organisation.

Oddly impressed with the 'White Dragon', Dazai learns Shibusawa's name - and as such, the head of the Dragon's Head Conflict. A Mafia building crashes into the plaza, along with many other buildings belonging to different organisations.

Despite all the organisations now participating in a single war, Dazai goes missing.

The day before the conflict ends, Shibusawa meets a mysterious man standing before him outside Draconia's collection room. The man asks why Shibusawa seems displeased, seeing as he's obtained everything he wanted. Shibusawa disagrees, feeling an emptiness that tells him there's more in store, despite his collection of valuable materials and corpses, a result of his obsessive collecting.

The man claims nothing material will fulfil Shibusawa, not money, nor violence, so says an "old acquaintance" of his.

Shibusawa recalls a memory from childhood, playing with tin like a toy, and wonders how he got from that point to how he is now, and wonders what he thought of that tin as a child. Like a bored child, he began breaking all he obtained. The man says it is simply the way God intended him as. Puzzled, Shibusawa asks if he should curse God, but the man clarifies, saying Shibusawa simply destroys playthings and moves on. Seemingly content, Shibusawa says it's what they should do.

At Port Mafia's headquarters, Ōgai Mori informs Chūya and Ryūrō Hirotsu of the situation. When it comes to organisations, Mori has the intellect to think of counterattacks ideal for the mafia, even if it's nonetheless a dangerous situation. However, the "White Dragon" poses a different threat - being a mysterious, unknown individual Mori knows nothing about. Throughout the conflict, four major criminal organisations perished. The Port Mafia stands as the last remaining major underground force, but even they haven't gone unscathed, losing the Executive 'Colonel', and another missing: Dazai.

Chūya insists they help anyone other than Dazai, but Mori ignores him, asking Hirotsu for any new information. Hirotsu elaborates many defeated comrades committed suicide against the powerful, unknown ability. As for Dazai's whereabouts since the building's collapse, the only new information Hirotsu knows is that Dazai recently bought a new microscope. In Dazai's office, Chūya breaks the microscope, revealing a transmitter, meaning Dazai intentionally got himself captured. Irritated, Chūya storms out, intent on getting his motorcycle to confront the "White Dragon" and Dazai. Hirotsu warns him not to go alone, but Chūya tells him he intends on using Corruption, much to Hirotsu's shock.

On the final day of the conflict, Chūya storms through streets and buildings to Dazai and the "White Dragon". An electrokinetic ability user attacks him but Chūya neutralises the threat with ease. Dazai sits patiently waiting for him, handcuffed with enemies aiming guns at his head. Once Chūya makes his presence known in the building, Dazai makes his move, calling Chūya late, and orders him to finish the job. With his ability, Chūya obliterates surrounding enemies. The two reach Draconia, where Shibusawa sits, burning valuable gems in a fire.

Chūya demands to know where his allies are, and Shibusawa says all six of them killed themselves after being caught. Enraged, Chūya activates Corruption. The ferocity of Corruption essentially causes a bomb-like reaction within the building, and spreads throughout its perimeter, ultimately ending the Dragon's Head Conflict.

Involved Parties

 * Port Mafia
 * Tatsuhiko Shibusawa
 * Fyodor Dostoyevsky
 * Special Ability Department
 * Gelhart Security Service (marine force, essentially pirates)
 * Shadow Blade (illegal arms dealer, destroyed)
 * Bishop's Staff (religious organization, destroyed)
 * KK Company (contraband merchants, destroyed)
 * Takasekai (destroyed after Leader's demise)
 * Strain (overseas organization, contributed nearly 80% of casualties)

Post-Conflict

 * The five orphans are adopted by Sakunosuke Oda.
 * Takasekai's leader is killed, leading to the organization's demise.
 * 'Twin Dark Black' forms.

Trivia

 * The conflict's details are elaborated upon in an event from Bungo Stray Dogs: Mayoi Inu Kaikitan.