Ōgai Mori/Synopsis

The Great War
Much of Mori's history outside the underground is unknown, including how he joined the Port Mafia. Fourteen years prior to present events, Mori operated as the head military physician for an infantry corp during the Great War. Here, he drafted Akiko Yosano into the war despite her only being 11 years old. He left Yosano the task of healing any wounds the soldiers sustained, meanwhile keeping a very close eye on her and her interactions with the soldiers. As a result, he developed a reputation for his intimidating behavior, going as far as drawing a gun on soldiers. Much to Yosano's chagrin, he frequently referred to her as 'his' and fawned over her harsh, cynical attitude towards him.

Mori noticed Yosano's growing friendship with one of the soldiers and learned this man understood the corps' specific role: a group of ability users meant to showcase their usefulness in the war to the military's top brass. Mori realized this means the man somehow accessed his essay "The Immortal Regiment", a classified document meant only for the emperor. In jeopardy of Yosano learning Mori's true intentions, Mori cut their conversation short, telling Yosano she still has patients to treat. He told an obedient Elise to lead the way.

The war raged on, and the unit became increasingly dependent on Yosano's ability. Using Yosano's ability to keep a constant stream of physically fit soldiers, Mori forced Yosano to use it on even the mentally traumatized, soldiers begging to return home after countless horrific injuries and near-death experiences. Because of this, the unit never receives orders to retreat, and more blood spilled. When the soldier Yosano befriended got a minor wrist fracture, Mori insisted on using Yosano's ability so he can immediately return to the frontlines. Exhausted and scared, Yosano refused. Mori correctly assumed Yosano wanted him healed away from the battlefield, sarcastically calling her refusal a dilemma - as her superior, he must give her orders, but couldn't resist a little girl's wishes. He suddenly gripped her head, calling her 'different' and ordering her to heal the soldier.

He then listed off histories of armies 'failing' to adapt to evolving weaponry and strategy, leading to their downfalls. Now, ability users reshaped war, and Yosano's only role was to make the military understand that shift. He warned her the country 'will be destroyed' otherwise. Regardless, Yosano defied him, pointing out she only wanted to save lives. Consequently, Mori coldly shot the soldier in the chest, putting him on the brink of death and leaving Yosano no choice but to heal him. The unit lost many soldiers to death thanks to Mori's plan and leads soldiers to direct their resentment towards Yosano for 'trapping' them in war. Even the soldier she grew attached to hung himself, pushing Yosano over the edge and breaking her mentally. She was soon admitted to a mental hospital, putting an end to the immortal regiment.

At some point, Mori returned to Yokohama, and before Yukichi Fukuzawa fully established the Armed Detective Agency, Mori ran an underground clinic that operated as neutral territory for the criminal world. By this time, Port Mafia's boss's mental state already deteriorated into a bloodthirsty state, and Mori answered only to Sōseki Natsume.

Here, he met his 'bodyguard', Fukuzawa, casually asking him to move medicine boxes. Fukuzawa denied the assumption he's operating as a bodyguard, instead of acting on Natsume's orders. Mori teased him that he'll get rusty if he started slacking. A pair of gang members interrupted their banter, one of them suffering a grievous gunshot wound. Mori ordered them not to start a fight, as the person who shot him was being treated as well. Mori assured Fukuzawa his clinic is neutral ground, and his clients always had plenty of 'stories to tell'.

Later that night, Mori was attacked and held hostage by men collecting intelligence on the Port Mafia's fortune. However, despite being beaten and tied up by them, Mori remained indifferent and nonchalant, complaining about an itch. One of the men lashed out, punching him, to which Mori casually mentioned it 'hit the spot'. The man told Mori his group plans on using the mafia's increased violence to use them as scapegoats, going as far as to steal and use their firearms.

Mori concluded that the group is illegal immigrants, thus the city's equilibrium meant nothing to them. He recalled them stealing medical drugs from a medical transport truck to sell on the black market. Mori noted his love of Yokohama, even with his bloody underbelly, suddenly taking a sinister nature and condemning the men as 'parasites' leeching off the city's resources. He then addressed Fukuzawa, who arrived after having killed over 20 of the group's men. Mori used Fukuzawa's arrival to distract the leading man, freeing himself of his restraints and cutting open the man's throat with a medical scalpel.

With the enemy defeated, Mori informed Fukuzawa that his plan to feign capture worked. Knowing where the group's base is, he determined it's prime time to counterattack, revealing this to be all part of Natsume's own plan. This effectively marked the beginning of Mori and Fukuzawa's partnership under Natsume's instruction. Between Mori's intellect and Fukuzawa's strength, the two were seemingly unstoppable.

Three years after the war's official end, Mori finally discovered Yosano's whereabouts. Ignoring her broken state, Mori intended to use her once more; however, Fukuzawa learned of Mori's scheme. In an effort to save Yosano, Fukuzawa fought Mori, questioning Mori's humanity. Mori argued that Yosano is vital for the tripartite framework and Yokohama's peace, claiming an 'immortal regiment' against Port Mafia's current boss would be the best way. Fukuzawa condemns Mori's heartless strategy, but Mori claims 'heart' has no place in war. Ultimately, the battle dissolved their alliance. While the full details of the battle are unknown, Mori ultimately lost Yosano to the Armed Detective Agency.

Fifteen Arc
At an unknown point in time, Mori eventually rose to a position of high standing the Port Mafia, acting as the Boss' primary physician and right-hand man. During this time, he eventually met Osamu Dazai, at the time a suicidal, shrewd boy that found himself in Mori's clinic. Upon learning of Dazai's intelligence, Mori decided to use him as insurance in assassinating the ill Port Mafia boss, and the two worked as accomplices. Dazai was to be Mori's 'witness' of the late Boss bestowing leadership upon Mori.

However, Mori's intention was for Dazai to have committed suicide soon afterward, taking the truth of Mori's murder with him in death. Dazai's many failures proved both an obstacle and an advantage for Mori. This proved a rare miscalculation on Mori's part, as he failed to correctly read Dazai's intentions and nature. Mori denied Dazai's accusations, pointing out how simple it would've been to let Dazai die instead of treating him from failed suicide attempts. He reached the conclusion he could not let Dazai die, as the former boss' remaining supporters would quickly know his 'death' was, in fact, a murder conspiracy.

Although he largely underestimated Dazai's intelligence and dark nature, Mori also found his mistake to lead to a new advantage. He found someone disturbingly similar to him in nature, and, as a result, a competent future right-hand he could 'trust', viewing Dazai as a 'diamond' in need of polishing. Ultimately, Mori indicted Dazai into the Port Mafia, lending him the 'Silver Oracle' and giving him incredible amounts of power for just his first official task as a mafioso - investigate the rumors of the former Boss 'returning' from the grave in Suribachi City. Just before Dazai left, Mori asked him why Dazai wanted to die so badly, but, as expected, received no answer.

During Dazai's mission, Mori calls him to receive affirmation that the Port Mafia's predecessor returned surrounded by black flames. They're unable to continue to speak due to someone attacking Dazai. It's implied Mori arranged multiple guards to Dazai and Hirotsu for this mission with the purpose of obtaining Chūya Nakahara. During this confrontation, a mysterious black explosion knocks the group out.

After retrieving them, Mori has Chūya restrained in his office by the hyperspace ability of his sub-executive Randō. A 'meeting' between the two and Dazai commences. The two boys argue upon sight, and Mori interrupts them to get to the point: asking Chūya about the explosion. He asks Randō to leave them be, and after getting him to leave, he bluntly asks Chūya if he'd like to join the Port Mafia. This infuriates the boy, which Mori anticipates, and understands his resentment against the Port Mafia thanks to the late boss. He acknowledges the mindless havoc his predecessor wreaked over Yokohama, and notes he 'died from illness', asking Chūya if he'd be anxious by rumors of him suddenly returning. However, Chūya does not believe him, quick to note Mori's desire for power and doubt his 'help' as the predecessor's doctor. Mori frankly admits to killing the former boss in an entirely calm, cold manner, noted to be the 'demon that devours demons' and 'incarnation of evil'.

With this reveal, Mori takes back his invitation to Chūya, instead of arranging a deal: Chūya works alongside them to solve the rumors, as they both benefit from the information the mysterious Arahabaki rumors surround them. He warns Chūya that if he refuses, he'll kill the Sheep members. This makes Chūya snap, breaking the restraints and attempting to punch Mori, but Mori holds up a transmitter just before getting punched, from which members of Sheep can be heard yelling for help, forcing Chūya to relent.

Settling the matter, Mori informs Dazai that Chūya is the epitome of violence, but that's simply the core nature of the Port Mafia. The way to control a situation is by crafting as many disadvantages to resisting them as possible: simply put, fighting fire with fire. Dazai questions the purpose of teaching him this, to which Mori smiles and merely repeats the question to Dazai in a knowing manner.

Chūya demands Mori to tell him information useful to him, and the group returns to the rumors surrounding the predecessor and Arahabaki. Mori shows footage of the predecessor in the Port Mafia's highly guarded vaults, where the supposed specter mentions Arahabaki's name. After discussing Arahabaki's origins, Mori asks Dazai's opinion, and the boy dismisses the predecessor's 'return' as impossible, instead of theorizing someone trying to use his 'return' to cause an uproar against the current Boss. Mori nonetheless argues that the overwhelming violence and wrath the predecessor caused, and Arahabaki's reputation as a 'wrathful god' match up too well, and it's impossible for an ordinary person to access the high-security vaults. Dazai asserts an ability user's doing, all in order to turn people against Mori.

Mori orders Dazai to uncover the truth, which Dazai reluctantly agrees to, but points out there's not enough time for him to accomplish anything alone. Mori 'reassures' him he won't be alone, deciding Chūya will work with him. Against their protests, Mori points out Chūya is in no position to refuse orders. He smiles, ignoring the boys' displeasure and anger, summarising that as the culprit is against the mafia, it'll be easier for an outsider to collect information, but to ensure Chūya doesn't betray them, Dazai will act as surveillance, as his nullification ability is ideal against Chūya.

Mori mentions a third, 'most important' reason, but refuses to tell them, instead of calling it his intuition. He warns them they won't accomplish anything if they keep arguing, and if he hears reports of their arguments interfere with the mission, they know what will happen. He asks for their answer, receiving only tense silence, and asks them again, and the two finally and reluctantly obey his orders. Satisfied, Mori dismisses them, saying he looks forward to hearing good news. Once left alone, Mori muses to himself, remembering a lesson Natsume Sōseki taught him, relating to why he forces the two boys to work together. A philosophy that only diamonds can polish diamonds - that only those with high potential can bring out another's high potential. Using Dazai and Chūya, Mori intends to verify this claim for himself.

Dazai laters contacts Mori after running into Shirase and two other Sheep members, requesting the ones held hostage by the Port Mafia be released. Mori approves the request.

Months after Rando's reveal as a traitor and his burial left in a makeshift gravestone, Mori continues to lead the Port Mafia with no issues. He assigns Dazai, now an official mafioso, as the commander for one of the mafia's troops, and issues the first order to eliminate the GSS and Sheep, the Port Mafia's most active rivals thus far. However, the truth behind this task is to recruit Chūya, knowing of the Sheep's resentment against him. Using the Sheep members' lives as leverage, it's an effortless task having Dazai convince Chūya to join the Port Mafia.

Later, Mori walks down a corridor of the headquarters with not only an injured Dazai but the recently retrieved Q. Mori admits he is unaware of the child's gender, intending to search through certain documents to find out. During the conversation, Chūya, alongside Kōyō Ozaki, run into them. The boys instantly argue. Kōyō questions Mori's decision to allow them both in the Port Mafia, but Mori insists it's fine.

Chūya asks about the black hat in Mori's possession, to which Mori explains it's part of the mafia's tradition to have the person responsible for 'inviting' a new member gift the new recruit with a piece of clothing. Mori points out Dazai's new coat was Mori's gift to him, and his gift to Chūya is the hat. Chūya notes its age, but Mori assures him it isn't a simple hand-me-down. During the Port Mafia's destruction of Rando's home, Mori looked over several of his possessions, the hat is one of them. More importantly, are military documents of highly confidential material. It reveals the research facility Chūya was found in belonged to the military, and the main purpose was to combine abilities with existing beings, that being: artificial abilities.

Mori refuses to let Chūya see the documents, stating that they're exclusive to executives. If Chūya wants to see them and discover the truth of his origins, he'll have to rise through the ranks. Mori points out Dazai will easily become an executive long before Chūya and asks if Chūya accepts the challenge. Chūya asks Mori what it means to be a leader, and Mori returns to his belief of being both their leader and 'slave'. He'll place his subordinates where they're best suited, using and discarding them if needed. To him, there's no atrocity beneath him for the sake of both the Port Mafia and Yokohama City as a whole. His words inspire Chūya, who's quick to pledge his life to the Port Mafia and city.

Dragon's Head Conflict
It is during Dragon's Head Conflict that, after the death of 'Colonel', a former executive, that Mori assigns Dazai an executive position. He largely leaves the conflict to Dazai's discrepancy, and notes this as the beginning of the infamous partnership 'Twin Dark', their power, skill, and dynamic mirroring that of Mori's and Fukuzawa's former partnership.

Dark Era Arc
Mori summons Sakunosuke Oda to his office, but during Odasaku's attempts of addressing the boss, Mori is too occupied insistently trying to convince Elise to wear a dress he got her. Elise rejects Mori's pleas at every turn, admonishing his apparent desperation. It's only after Oda interrupts their back-and-forth that Mori acknowledges him, freezing in place. He apparently stares expectantly at Oda, possibly for assistance dressing Elise up, however, this only ends in awkward silence. He seems caught off guard when Oda reminds him he summoned him, and asks Elise why he did so in the first place. Elise offers no answer.

Mori returns to his desk, pressing a button that tints the windows a dark grey, darkening the office. Befitting of a mafia boss, he's suddenly accompanied by two bodyguards that stand on either side of his chair. He attempts to strike up a conversation with Odasaku, but points out Odasaku doesn't speak up much. Mori confirms that no one saw Odasaku arrive here, and gets to business. He notes that Dazai once told him Odasaku has no ulterior motives, being a direct individual, which is a rarity in the Port Mafia. He even acknowledges Dazai calling Odasaku's peculiar nature a 'balm for the soul'.

He proceeds to the task at hand, occupying himself with an unlit cigar he casually plays within his hand, informing Odasaku he wants him to find someone. Odasaku questions Mori's intentions, and Mori admits normally members as low-ranked as Odasaku get stuck with, essentially, suicide missions. However, on this occasion, the matter requires Odasaku specifically. The 'someone' is Ango Sakaguchi, a mutual friend of Odasaku and Dazai, alongside the Port Mafia's informant. Odasaku's composure impresses Mori, thus the boss continues to brief him on the rescue mission. As Ango's whereabouts and condition are unknown, it is imperative to retrieve him. His role as an informant leaves him a goldmine for all of the Port Mafia's vital secrets in the hands of enemy syndicates. However, Mori further claims that regardless of circumstances, he wants a member as talented and capable as Ango assisted as soon as possible.

When Odasaku agrees to the assignment, Mori notes he's heard of Odasaku's reputation. His composure and level-head make him a valuable asset, and Mori expects great things from him. He proceeds to write a Silver Oracle for Odasaku, granting him written permission to order anyone beneath the Executives without question, however, Mori goes even further, explicitly stating Odasaku can use it to order the Executives as well.

This brings him to Odasaku's close friendship to Dazai, encouraging Odasaku to utilize Dazai's skill with the mission. He comments on Dazai's poor reputation but emphasizes that Dazai's intelligence and skill may one day lead him to usurp the Port Mafia from Mori - that is, by killing him. He smiles upon saying this, leaving Odasaku in stunned silence. Mori states he hopes to hear great news from Odasaku.

Just before Odasaku leaves, Mori compliments the pistol model Odasaku keeps in his holster. He asks Odasaku about the rumors that he refuses to kill anyone, to which Odasaku confirms. Mori asks why that is, but after telling Odasaku he's only asking out of "personal interest", Odasaku plainly states he'd rather not tell him. This briefly surprises Mori, but he quickly recovers, dismissing Odasaku and reiterating he hopes for great news from him.

During the incident where Mimic slaughters the orphans Odasaku's looks after, Mori attends a meeting on a ship between himself, Ango, and Santōka Taneda, the commander of the Special Abilities Division. Mori casually greets Ango, but the man avoids responding. Despite their conflicting positions, any present Port Mafia guards and the Special Forces are unarmed during the meeting. The meeting is unofficial, and during it, Mori casually asks Taneda if he knew of any nearby ice cream parlors. In response, Taneda notes he should bring something back for his men, stating they'd love to see Mori's head.

Their passive-aggressive 'banter' does not alleviate the tension in the air, with only Ango breaking the silence. He explains that a deal between Mori and Taneda ensured his safety, alongside the Port Mafia wiped out Mimic. Although Mori agrees to the first term, he lightly points out Mimic is giving the Port Mafia its fair share of trouble. He smiles the entire time and gives Ango a stare that 'signals' the continuation of their arrangement. In exchange for Mori's cooperation, Taneda gives the Port Mafia a black envelope.

After Dazai fails to dissuade Odasaku from attacking Mimic on his own, he confronts Mori about the ordeal. Aware of why Dazai arrived, Mori assures him that he's sure a 'genius' like Dazai has a sure-fire plan for the fight against Mimic. His 'praise' shuts Dazai down for a moment, making it evidently clear even Dazai must tread carefully with his words around the Port Mafia's boss. Mori approves Dazai's request for giving Odasaku back-up, noting that being straightforward in his intentions is one of the best methods of negotiations, but before issuing the order, he asks Dazai why he wants to do so in the first place.

Dazai's explanation fails to convince Mori, who points out that, while a valuable ally, Odasaku is ultimately one of the lowest-ranking Mafiosi they have, and questions if he's really worth sending skilled men to save just one low-ranking member. Dazai plainly states he is, and his blunt response surprises Mori into a brief, yet profound silence, where both of them understood each other's intentions clearly in that single moment.

Mori points out he doubts that Odasaku doesn't want help to begin with, and asks what Dazai thought about that. Dazai is unable to answer, and Mori follows his point up by revealing the black envelope. He explains that being the Port Mafia's boss means being both its leader and a slave to it. He must be willing to perform any necessary and "logically conceivable" atrocity, all for the sake of ensuring the strength, the value of his subordinates, and defeat their enemies. His explanation builds up to a vital reveal, sliding the mysterious envelope to Dazai.

The truth behind the war between Mimic and the Port Mafia comes to light to Dazai, who abruptly dismisses himself and attempts to leave. Mori asks where he's going, and Dazai naturally responds he would go to Odasaku. But before he can leave, four guards aim their firearms at him. Dazai turns to see Mori smiling at him.

Mori orders him to stay, to which Dazai reluctantly obeys. He informs Mori he knew something felt off about the conflict, admitting he suspected the Special Ability Division to be behind it, but facing Mori, knows he was wrong, a rarity for Dazai. With a full understanding of the situation now, he sums up Mori's actions and motivations, including that Mori knew Ango was a double spy who infiltrated the Port Mafia two years ago to keep tabs on them when he sent Ango to investigate Mimic, which Mori never denies nor confirms, admiring Dazai's sharp perception. Dazai continues on, pointing out the Division would have incredible difficulty suppressing Mimic on their own, so Ango was tasked with leaking Port Mafia information to Mimic, guaranteeing they'd attack Port Mafia, forcing the Port Mafia's hands - exactly as Mori would want.

Mori claims Dazai gives him too much credit, pointing out it isn't that easy to manipulate the Division, as they're much more powerful than they let on. Dazai acknowledges this, noting that even the Port Mafia must tread carefully or risk being snuffed out, and argues this is why Mori orchestrated such an elaborate scheme in the first place - all for a single black envelope. When Mimic became an issue in Yokohama, Mori took advantage of the situation and offered the Port Mafia's assistance in exchange for the envelope.

Smiling, Mori pulls a government-certified permit from the envelope. The certificate, being a permit allowing the Port Mafia to operate as a legally recognized abilities organization.

Dazai goes deeper into realizing Mori's scheme, assuming it started when Mori sent Ango to Europe for business. He learned of Mimic that way and figured they'd be the easiest way to set his plan into motion, having Ango contact them, and illegally aiding in their escape and infiltration to Japan. All to force the Division's hand, and obtain an ability permit.

Mori confirms Dazai's accusations and asks if there's anything truly wrong with Mori's actions. In his eyes, he obtained an ability permit, which guaranteed a way for the Port Mafia to conduct their illegal activities without "legal" interference from the Division. And, as of now, Odasaku would wipe Mimic out, eliminating a dangerous threat to the Port Mafia. Ultimately, for the Port Mafia, the arrangement is a win-win situation, at the expense of a single, low-ranking mafioso.

From a logical standpoint, Dazai cannot argue against Mori's methods, but he attempts to, unable to accept how far Mori went, pointing out that no one should've been able to find where Dazai helped Odasaku hide the children. No one except Mori, that is, realizing Mori leaked the children's location to Mimic. As such, Mori had Mimic murder the children to push Odasaku over the edge, knowing he'd be the best candidate for defeating Mimic.

Nonetheless, Mori's response remains the same, explaining that the Port Mafia has always committed the worst crimes and violence to obtain their goals, and this is no different. No matter how horrific the situation became, in the situation of strictly thinking about Port Mafia's well-being, Mori was 'right', and Dazai 'wrong' in questioning his methods. Unable to debate any further, Dazai attempts to leave again, but Mori tells him not to. Dazai states Mori wouldn't actually kill him since he gains nothing from that. However, Mori questions what Dazai gains from disobeying his boss. Dazai dismisses Mori's attempt to make sense of his intentions, simply pointing out Odasaku is his friend, finally leaving Mori, who watches him leave with a faint smile.

Two weeks after Odasaku's death, Mori sits in his office, listlessly reading over the Silver Oracle he bestowed to Odasaku, having retrieved it from the building Mimic was wiped out in. A subordinate points out to him it's been two weeks since Dazai disappeared, suggesting they organize a meeting in order to discuss who would succeed Dazai's executive decision. Indifferent, Mori decides not to have the meeting, instead of keeping Dazai's position open. Alongside the Silver Oracle, he has the ability permit on his desk. The permit is invaluable to the Port Mafia, more than making up for any financial losses and lost Mafiosi. Alongside these losses was Dazai abandoning the Port Mafia.

With the permit in his hands, all of Mori's plan succeeded. He folds up the Silver Oracle into a poorly-made paper plane, throwing it, and it almost immediately crashes to the floor. In the silence, Mori laments how things would get "boring" in the Port Mafia now.

Armed Detective Agency vs. Port Mafia Arc
Mori arranges the Port Mafia's manhunt on Atsushi Nakajima, tasking Ryunosuke Akutagawa and Ichiyō Higuchi with the job.

After Akutagawa's defeat, Mori details his dire condition to Higuchi, warning her he may never wake up, much to Higuchi's worry. Unperturbed, Mori assures her that what matters is their attempt, not their failure. Naturally, the reassurance doesn't console Higuchi. Mori continues, bringing up the illegal smuggling group Akutagawa slaughtered, Karma Transit. With Akutagawa's injuries and Karma Transit's grudge, Akutagawa is now a liability. Although Mori acknowledges Akutagawa's worth in the Port Mafia, he questions Higuchi's place as a mafioso. Despite knowing Karma Transit kidnaps Akutagawa, Mori never issues an explicit rescue mission, leaving his subordinates to their own devices.

The Guild Arc
Posing as a civilian doctor in the city, Mori loses track of Elise, calling her name to try and find her. Jun'ichirō Tanizaki shoves him out the way searching for his sister, with Atsushi crouching down to ask Mori if he's okay, unaware he's speaking to the Port Mafia's notorious leader. As a result, Mori is trapped by Lucy Maud Montgomery's Anne of Abyssal Red alongside the two detectives and many street passersby.

After witnessing Lucy's power, Atsushi urges Mori to run, but Mori refuses, telling him he's looking for his 'daughter' and showing a photograph of Elise. It's possible Elise is trapped in Lucy's room, so he can't leave. For the majority of Atsushi and Tanizaki's battle against Lucy, Mori plays the role of an innocent civilian. After Atsushi attempts to escape for help, Mori stops him, advising him with simple game theory: when the enemy attacks, fight back with all you have. When Atsushi isn't completely convinced, he reminds Atsushi that many people depending on him are still trapped.

Although this helps Atsushi, he's nonetheless 'caught' by Anne. Lucy gloats, aiming at Mori as her next target, however, Mori shows his true colors to her alone. Mori gives a menacing smile that sends chills down Lucy's spine, warning her she's not dealing with a normal man. His frightening gaze and aura are enough to scare even Anne. Mori tells Lucy she's already lost, revealing Atsushi and Tanizaki's plan to defeat her. After Lucy's defeat, Mori and everyone else are freed from Abyssal Red, and much to his joy, Mori finds Elise. When he asks where she went off to, Elise tells her she hid from him to make him upset. Right before leaving, Mori leaves Atsushi with one last piece of advice: no matter the hardship, there's always a logical, optimal solution. If he finds himself pushed into a corner, he mustn't ever forget that. Mori leaves with Elise in tow, rendering Kyōka Izumi a trembling mess, as she's the only one who recognizes who he truly is.

Mori arrives at a secluded alley, where major mafiosi surround the corpse of a Guild assassin. At his arrival, his subordinates all bow down to him out of respect. Confirming the assassin's death, Mori gives the order to kill both the Guild and Armed Detective Agency.

Having found Kyōka, Mori exchanges a short conversation with Kōyō before she departs to retrieve her former protégé. During their confrontation, Kōyō reveals Mori gave her permission to retrieve Kyōka, instead of eliminating her as a traitor. After being informed of the Guild's attack and Kōyō being missing in action, Mori grits his teeth in frustration, but later simply decides to kill Fukuzawa in retaliation. He arranges for assassins unaffiliated with the mafia to save them the trouble, allowing them to fully focus on the Guild.

The assassination attempt inevitably fails, but scandium marks on the assassins' sleeves allow them to track Fukuzawa's moves. Using this, the Port Mafia locates the Agency's hideout, and Mori has Chūya confront them. As part of Mori's plan, the Port Mafia leaks the whereabouts of Naomi Tanizaki and Haruno Kirako to the Guild, forcing the Agency to take action in hopes of the two enemies taking each other out, lessening the burden on the Port Mafia.

Meanwhile, Mori plans on attacking the Guild's major base, playing darts with his scalpels (and missing every single time). Much to Elise's chagrin, Mori takes one of her crayons to write a letter to the Guild. The letter reaches Nathaniel Hawthorne and Margaret Mitchell, full of empty pleasantries before stating he intends on destroying the S.S. Zelda and killing both Guild members. He assigns Motojirō Kajii and Akutagawa the task.

When Chūya reaches the Agency's hideout, he reveals that they've leaked Naomi and Haruno's whereabouts to the Guild. According to him, Mori said that while the Agency would know it's a trap, they'd make a move nonetheless, driving in Mori's understanding of the Agency's ways.

Determined to wipe out both organizations, Mori goes as far as to release Q from their imprisonment, much to Dazai's shock. He also sends Gin and Higuchi to confront the man, having Higuchi send Mori's usual mocking question to Dazai: if he wants to return to his post as an executive. As Dazai's the one responsible for Q's imprisonment, Mori arranged Gin and Higuchi to 'protect' him from Q's grudge.

Although Mori succeeds in destroying the S.S. Zelda, his other two schemes fail to weaken the Agency. And as a result of their retreat, Q is captured by Howard Phillips Lovecraft as part of the Guild's own plan to use them to burn Yokohama to the ground. With Yokohama in a state of chaos because of Dogra Magra, Mori has his major mafiosi defend their territories from any damage.

Although the incident is quickly quelled, the Guild can reactivate it at any time with Q in their clutches. Mori arrives in one of the Port Mafia's shell companies, filled to the brim with the corpses of many Mafiosi. Having lost 18 direct members and over 100 affiliates, Mori smiles bitterly, ironically wondering aloud how he could face the former boss. Just then, Kōyō returns with a letter from the Agency to work together. With an amused smile, Mori agrees to attend.

Later, Mori and his entourage are welcomed by Dazai to commence the secret meeting. Mori and Fukuzawa state their mutual distrust towards each other's organizations and in an alliance, citing how no one can oversee and stand on neutral ground between the two parties. Fukuzawa then urges Mori that they end it all between the two of them, hence clashing with each other.

In the end, the two parties arrive at the conclusion that they cannot have an alliance. As the mafia leaves, Mori tells Dazai that his invitation to return as a mafia executive still stands, to which Dazai quips if the boss is quite afraid that he might kill him soon like how Mori killed his predecessor.

At night, Mori is updated by Hirotsu that their forces are in position for the counterattack against the Guild. Hirotsu also discusses the former boss' instability and tyrannical leadership that almost razed the city to the ground. Mori asks him to go straight to his point, to which Hirotsu acknowledges that Dazai, among many others, most likely understands why Mori murdered the former boss. Mori admits that he does not regret his past actions, though he finds it unfortunate that Dazai did not last as his right-hand man. Despite not openly forging an alliance with the Agency, Mori sends Chūya to aid Dazai, resurrecting Yokohama's vicious duo, Twin Dark, for one night to crush their mutual enemy.

When Atsushi solo infiltrates Moby Dick, Mori contacts Dazai, much to the latter's cringe. Mori proceeds to tell Dazai that, though the mafia and the Agency have agreed not to hinder each other during the war, he has received a report and can no longer adhere to the treaty, seeing that Akutagawa has also infiltrated Moby Dick.

As the three-way conflict ends, Mori celebrates with Kōyō and Chūya to their success, treated to one of the latter's prized wines. Mori asks Kōyō why she chose not to escape when she was confined in the Agency given that it must have been easy with her ability. Kōyō retorts that it must have been due to the wonderful tea that they served her at the place. If Kōyō were to leave the mafia, with her powerful skills, he admits that nobody might be able to stop her. Kōyō assures him that she has an inept boss to help in reviving the mafia, clarifying that she only hates the previous mafia and that she is now content with the current organization. Mori is gladdened with her response, though he jests that he is only interested in young girls, to which Kōyō asks him to shut up.

The Guild Aftermath Arc
Following the end of the Guild war, Mori orders his subordinates that they are still prohibited from antagonizing the Agency even after the three-way conflict. Though Higuchi initially questions it, Mori assures her that he has taken it into consideration from every perspective. He then tasks Gin to disseminate the order to her fellow mafiosi.

Some time later, Mori and Kōyō are informed by Ace that Fyodor Dostoevsky, the mastermind behind the sinking of Moby Dick, has been captured courtesy of his professional kidnapper. Mori wonders what Fyodor is like, to which Ace mutters under his breath that the man is like a soulless vampire. In any case, Mori remarks that the Russian shall experience the mafia's retribution firsthand, to which Kōyō asks whether her torture squad shall handle it. Ace interjects and volunteers to handle it himself, which Mori allows. As Ace leaves, Kōyō worries about a disloyal executive like Ace handling the case, though Mori comments on how his strength lies in his finances, looking forward to what the executive shall do.

Cannibalism Arc
When ability users are being attacked by a masked assassin at night, Mori orders the Black Lizard to track and infiltrate the alleged suspect's hideout, though he learns from Hirotsu that the place is empty. He then allows them to enact their usual plan as their next course of action. As he and Elise board their car along the streets, the vehicle explodes courtesy of the masked assassin. Elise saves him through levitating, upon which Akutagawa contacts and updates him that their prey has been ensnared. Mori then instructs him that it is their turn to bite him down.

A police officer inquires about the incident. Mori makes up a lie that triggered the explosion, only for the officer to stab him and gets revealed as Fyodor when Mori removes his cap. As Fyodor runs through the crowd to escape, Mori immediately instructs Elise to chase him down, but to no avail. Thinking how Fyodor must have also planned the crowd density, Mori loses consciousness as the Cannibalism virus activates through his wound. Higuchi later rushes in to have him treated.