Yukichi Fukuzawa/Synopsis

History
In his youth, Fukuzawa grew up with his close friend Ōchi Fukuchi, whom he often called Gen'ichirō, and learned the way of the sword from the same government-run school of martial arts. They also had a mutual female acquaintance named Kin during this time. Fukuzawa and Fukuchi seemed to have had a friendly yet harmless rivalry over the years.

The Great War
During the Great War, Fukuzawa refused to enter the battlefield with Fukuchi, ultimately dividing their paths. Towards the end of the war, amidst a dispute over a ceasefire agreement, some war hawk bureaucrats advocated the expansion of their frontlines, but they ended up being found dead together with foreign military leaders who backed them up, which was presumably Fukuzawa's doing upon receiving instructions to assassinate the war hawks. From then on, after the incident, Fukuzawa never contacted the officials who ordered him and decided to take the secret with him to the grave.

The Untold Origins of the Detective Agency
Fukuzawa soon quit his job and became a lone wolf bodyguard, eventually garnering an infamous identity throughout Yokohama as a highly competent bodyguard. At some point, one of his clients had been killed, and he headed to her company where the suspected assassin was restrained. He soon met a 14-year-old Ranpo Edogawa who deduces that the company secretary was the true suspect who killed Fukuzawa's client. It was also during this time that he had a brief skirmish with the suspected assassin, whom Fukuzawa recognized as Sakunosuke Oda.

Fukuzawa treated Ranpo to red bean porridge, who talked about his bewilderment towards adults, his expulsions at school and work, and his genius parents. Figuring that Ranpo is quite special, Fukuzawa allowed the boy to come with him amidst his initial reluctance. They soon arrived at a theater, where Fukuzawa was hired to apprehend a criminal after receiving a death threat signed by an ambiguous "V". They were met by the manager, Ms. Egawa, who showed Fukuzawa the note regarding the murder, which Ranpo thought will happen.

To gather information, Fukuzawa and Ranpo questioned the performers, including lead actor Tokio Murakami. With Ranpo confident that the murder shall take place, Fukuzawa tried to assess his skills and asked Ranpo to deduce him. As the boy uncovered his secretive past with ease, Fukuzawa fully believed that Ranpo is special. When the play began, Fukuzawa scanned the theater to find the possible killer. He spotted a suspicious man, but Ranpo stubbornly complained during the play. Though he tried to calm him, Fukuzawa soon found Ranpo desperately shouting among the crowd on why nobody understood him, after which Fukuzawa took him out of the theater hall.

Fukuzawa discovered that Ranpo's parents essentially sealed away his skill for him to learn about the world like an ordinary person, knowing that society will come off as strange to him. However, Ranpo was left unguided after their deaths, causing him to misunderstand the world before he can fully comprehend it. To rein him in, Fukuzawa convinced that Ranpo is special because he has an ability, which is to see the truth in one glance. He also gave Ranpo a random pair of glasses that he claimed will help control his powers. Ranpo was later convinced that he, the world's greatest detective, must protect the simple-minded, ordinary people. He then asked Fukuzawa to return, as Ranpo assured him that the murder will occur in the next scene.

During Murakami's act, a knife suddenly pierced his chest, which was not part of the script. Fukuzawa rushed to him amidst the crowd's panic. News emerged that Murakami died en route to the hospital, while Fukuzawa worried that something might have happened to Ranpo, who had not yet returned. As he looked for him, he was informed that one of the audience members escaped, who turned out to be the suspicious man he spotted earlier. Fukuzawa thought that the man might have taken Ranpo, but Egawa approached him to relay Ranpo's instructions.

As Fukuzawa returned to his seat with several spectators, Ranpo appeared onstage to explain the mystery. In the end, Murakami, who was revealed to be the culprit, was taken away, and a police officer named Jun Mitamura thanked the two for their help. Ranpo replied that it was all thanks to his ability, but Fukuzawa tried to convince him that he is not an actual ability user, albeit to no avail. Mitamura took Ranpo with him, while Fukuzawa learned from Murakami that the latter and the playwright were told by a third party about the man in the suit, after which Fukuzawa was told that the playwright had been found dead.

Fukuzawa set out to find Ranpo, when he noticed a note from the boy stating that Mitamura was the culprit. Fukuzawa also found the cane of the man in the suit, where he discovered a hidden computer memory chip. Fukuzawa soon visited the detained Oda in his cell and inquired about his past clients who might have hired him to catch an ability user. Initially hesitant, Oda soon cooperated upon hearing that the mastermind is V. Upon locating Ranpo's location, overwhelmed Mitamura alongside five armed guards. Though Ranpo was thrilled with the bodyguard's prowess, Fukuzawa berated and lectured him never to risk himself to such danger again. In the end, the two made amends with each other.

From then on, Ranpo became attached to Fukuzawa, and, over the course of a year, Fukuzawa brought Ranpo to several odd jobs, albeit later losing his job as a bodyguard. Nonetheless, various clients sought Ranpo's detective skills alongside Fukuzawa's protection, eventually garnering the two considerable notoriety to criminal groups and individuals.

Later on, Fukuzawa brought Ranpo to an underground hall, where they were greeted by the man in the suit. Fukuzawa sought out the latter – Sōseki Natsume – for his help in acquiring a skilled business permit, as Fukuzawa realized his desire to continue helping other people even if it required him to lead an organization. With Ranpo at the forefront, he aimed to have him guarded and armed by gifted detectives suitable to carry out his vision, with which Fukuzawa established the Armed Detective Agency.

Post-War Era
During the celebration of the Agency's founding, Fukuzawa invited Fukuchi to the event, where the latter caused a ruckus that greatly annoyed Ranpo. Later on, Fukuzawa was entrusted by Natsume with the task of protecting Ōgai Mori who was still an active doctor at that time. Fukuzawa held suspicions towards Mori as soon as he met him in his underground clinic. On the same night, Fukuzawa effortlessly took out twenty guards on his own, while Mori feigned capture from foreign mercenaries to acquire intel from them. As Mori overwhelmed his captors, Fukuzawa and the doctor head to the enemies' base and defeated them all, after which they conversed about Natsume's Tripartite Framework.

Three years after the Great War's official end, Fukuzawa fought Mori after learning that Mori aimed to use Akiko Yosano's ability for his personal scheme. Mori argued that Yosano is vital for the Tripartite Framework and Yokohama's peace, claiming an 'immortal regiment' against Port Mafia's erstwhile boss would be the best way. As Fukuzawa condemned Mori's heartless strategy, their battle dissolved their alliance, ending with Yosano entering the Armed Detective Agency through Ranpo's invitation.

Port Mafia Arc
Fukuzawa's first appearance takes place after Atsushi took his "entrance exam" at the Agency. Because of the young man's ability to transform in a feral, giant tiger, the President wanted to test Atsushi's spirit. Fukuzawa eventually hires Atsushi and places him under Osamu Dazai's care.

After Atsushi's abduction by the Port Mafia and with several Agency members agreeing to leave the young man to his fate, Fukuzawa steps in at Naomi Tanizaki's initiative. Despite his organization entrusted at that time with the task to protect some government officials, Fukuzawa orders all Agency members to drop the mission until Atsushi's safe return, as, according to his words, nothing can be more important than saving a companion in danger. He is later seen along with his subordinates, talking about potential leads in Atsushi's disappearance. After hitting a dead end, he asks for Ranpo and his deductive-reasoning skills in exchange for the President praising him. With Ranpo having found where Atsushi is, Fukuzawa gives Kunikida the key to the Agency's boat and asks him to bring Atsushi back at all costs.

With Kyōka and Atsushi out of danger, Fukuzawa summons Kyōka's presence at the Agency. The young girl requests her right to stay from Fukuzawa who, having a very soft spot for cute things including Kyōka's face, cannot refuse. When police officer Minoura suspects Kyōka to be the young girl who is on the police wanted list for being a murderer, Fukuzawa eventually claims Kyōka to be his granddaughter. Minoura believes him as both wear the same stern looks and is "cut from the same mold".

The Guild Arc
When members of an American organization called The Guild pay a visit to the Agency, the leader of the Guild, Francis Fitzgerald, offers Fukuzawa a great amount of money in exchange for the Ability Business Permit, a document granted by the government allowing the Agency to run ability-based business. Fukuzawa dryly refuses, telling Fitzgerald that neither the lives nor the permit of the Agency can be bought, as the permit embodies the hope of the government and Natsume's efforts to found the Agency.

Riled up because of the bloody encounter between several members of the Guild, the Agency and the Port Mafia, with the former being victorious, Fukuzawa goes for a walk, unaware of Ōgai Mori's assassination plot against him. While discussing the upcoming evacuation of the Agency with Kunikida by phone, the President is attacked by second-class assassins. It soon appears that Fukuzawa is more than able to deal with them, thus revealing his unchallenged efficiency in martial arts. He gives the beaten assassins a threatening message for whoever is behind the murder attempt, warning them against laying a single finger on his subordinates; instead, he urges them to come at him and him alone.

Soon after, he is seen entering the new Agency hideout, warning his subordinates against the Guild and the Port Mafia since both organizations are seeking the demise of the Agency in the near future. Fukuzawa finds himself assigned to the defense team as protecting Akiko Yosano is the key to the survival of the Agency in the upcoming war. He is revolted when he learns that the Port Mafia used two of the Agency's clerks, Haruno and Naomi, as baits against the Guild.

After the large-scale Guild attack on Yokohama, Fukuzawa is seen giving treats to a cat during one of his walks; Atsushi appears, and the two engage in a long conversation. The President is asked by Atsushi to implement a temporary truce with the Port Mafia in order to overpower the Guild. As Dazai points the danger of such a meeting out to Fukuzawa, warning him about assassination attempts against the President, the latter replies that it is preferable to seeing his subordinates injured or dead.

At the meeting with Mori and the Port Mafia, Fukuzawa explains that while he is opposed to side with an illegal organization and therefore rules out an alliance, he advocates for a détente because of Atsushi’s plea. Mori points up the mutual grudges against each organization’s members and, above all, the lack of guarantees in Fukuzawa’s demand, as both the Agency and the Port Mafia could break the agreement without fearing sanctions. Fukuzawa offers to settle the score, “right here, right now”. With great speed, the two leaders attack each other, only to call it a draw as Fukuzawa puts his katana on Mori’s throat and Mori his scalpel on Fukuzawa’s. The President of the Agency eventually calls for a one-night truce in the name of their shared love for Yokohama and their status as protectors of the city against foreign ability users.

After the fall of the Moby Dick in Yokohama bay, Fukuzawa explains his ability to Atsushi who believes Kyōka to be dead because of the crash. All Men Are Equal only affects Fukuzawa's subordinates, inhibiting their powers so they can control them. Because she was willing to sacrifice herself in order to save Yokohama, Kyōka passed her own "entrance exam". She thus became a fully-fledged Agency member, fell under the range of Fukuzawa's ability and escaped moments before the crash thanks to her new control over Demon Snow. He is later seen attending the welcoming party for Kyōka at the Agency.

Cannibalism Arc
During one of his evening walks, Fukuzawa notices a trail of blood leading to a dark back alley. Following the stains, he eventually gets attacked by the Masked Assassin who targets ability users. At first able to counter the attacks of the Assassin, the President gets shot by a sniper lying in ambush, barely grazing him but effectively poisoning him. Later revealed to be Nathaniel Hawthorne working for the Rats in the House of the Dead, the Assassin flies away, and Fukuzawa collapses on the ground.

He is later seen at the hospital under Akiko Yosano's care, but with the doctor's ability unable to cure him, Fukuzawa is still unconscious. With Ōgai Mori poisoned in the same way soon after, a strange sigil appears on Fukuzawa. At the same moment, Fyodor Dostoevsky explains to Dazai what is happening to the President: both him and Mori have been infected with Cannibalism, a lethal virus destroying the internal organs of the hosts after forty-eight hours. In order to nullify one host's affliction, the other has to die before the virus outbreak.

After examining the President, Yosano tells Tanizaki and Kunikida that Cannibalism is indeed draining Fukuzawa's life force. A distraught Ranpo holds a vigil at Fukuzawa's bedside. The situation quickly festers as both the Agency and the Port Mafia seek to kill the leader of the other organization to save theirs. All Agency members thus protect Fukuzawa's room against the enemy.

Thanks to Tanizaki's illusion ability and Kenji blasting through a wall, they are able to evacuate Fukuzawa from the hospital by ambulance. Tanizaki stays behind in order to frame the Port Mafia, Atsushi, and Kunikida chase the alleged virus ability user, and the President is taken to an unknown but hopefully safe location. Ranpo's stern but restless attitude shows Atsushi that Fukuzawa's situation is far more serious than previously thought.

When the President's eyes open again, he finds himself in Anne's Chamber, a dimension created by Lucy Maud Montgomery in order to protect him at Atsushi's request. As Lucy is taking care of a gravely ill Fukuzawa, he holds up a shaky hand and implores to not fight with the Port Mafia, and protect the balance and peace of Yokohama over his life.

The attempt to find the virus ability user failed, time is ticking, and Fukuzawa's orders to not attack the Port Mafia are discussed by the remaining members while the President is still looked after by Lucy. Fukuzawa awakes once more, notices a sleeping Lucy, and tries to sit up despite the pain. He is then horrified as he hears Atsushi announce Katai Tayama's death through a walkie-talkie given to Lucy by the Agency.

Fourteen hours before the virus outbreak, Fukuzawa finally manages to get up. Before he leaves Anne's Chamber, Lucy asks him to tell her what he plans to do, in exchange for her having taken care of him; to which he answers, "see an old friend". Soon after, Yosano is extremely concerned at the news that the President is gone. It is later implied during a conversation between Naomi and Kirako Haruno that Fukuzawa went on his own in order to protect the members of the Agency.

Without prior planning, Fukuzawa and Mori meet at an old mansion where they fought side by side for the first time twelve years ago. They agree that a duel to the death is the only way to end the bloody feud between the Agency and the Port Mafia. Mori summons Elise and promises Fukuzawa that this place will be his final resting place. Fukuzawa grasps his katana and readies himself to battle.

As they clash with each other, Fukuzawa and Mori muse how they were invincible when working together years ago. Fukuzawa eventually manages to cut Elise into pieces, calling for the end of the Tripartite Framework. Mori explains that his death would ignite an even bloodied war between the organizations, whereas Fukuzawa's death would bring the war to a peaceful end. He suddenly stabs Fukuzawa in the throat with his scalpel, then apologizes for his dirty play while his opponent is heavily bleeding on the floor.

The apparition of Sōseki Natsume ultimately prevents Mori from dealing the final blow to the President of the Agency. Thanks to Natsume's intel, the Agency and the Port Mafia are able to track down the position of the Rats in the House of the Dead hideout and the virus ability user, Alexander Pushkin. When the man eventually exits the hideout, members from the Agency and the Port Mafia are waiting for him. Fukuzawa, alongside Mori, knocks Pushkin out, thus releasing him from the death sentence of the virus.

In the anime, it is implied that Fukuzawa made a complete recovery as a celebration is planned. While on a boat given by Fitzgerald, the Agency members apologize to Fukuzawa for having disobeyed his orders to not fight with the Port Mafia; the President says that the nature of their punishment will be decided later. He then congratulates them for their work on the matter and gives them a rare but genuine smile.

Because they disobeyed Fukuzawa's orders, several members are given punishment, such as Ranpo having to help a salesman at a shopping district and Tanizaki being the target for target practice.

Hunting Dogs Arc
One month after the Cannibalism events, a formally dressed Fukuzawa receives the Shikyuu Award during an official ceremony hosted by Vice Minister of Justice Tonan. The government thus acknowledges the major contributions of the Agency for public safety.

A terrorist organization named the Decay of Angels soon makes its presence known to the Armed Detective Agency by gruesomely murdering four government officials within a single week. Fukuzawa enlightens his subordinates about the very name of the organization. He explains that it refers to "angels" found in Buddhist scriptures and the five signs of their pending demise: garments are soiled, the flowery crown withers, the body's radiance fades, sweat pours from under the arms; every sign is linked to one of the four murders, thus leaving the fifth crime to be committed.

Ranpo refuses to take the case because of Mushitaro Oguri's warning about the fall of the Agency and Fukuzawa reminds him of the Azusa Yumi displayed in the President's office, though calling it a mere piece of wood. According to Fukuzawa, the Agency has to stop the murderer even if it means putting their lives on the line, not because of the award but because of the Agency's morals and values. The President thus lets Ranpo investigate the alleged fall of the Agency while the other members focus on finding the murderer.

After the Agency is falsely incriminated for the murders and is believed by the government to be the Decay of Angels, Fukuzawa is put under arrest and called "an enemy of the state". Right before his arrest, Fukuzawa was giving Mori a phone call and asked for the Port Mafia's protection over the Agency. Mori accepted on one condition: a member of the Agency must transfer to the Port Mafia. Fukuzawa forbade him to choose Yosano as she would not tolerate being Mori's subordinate again. Afterward, Mori lies to the doctor and tells her that Fukuzawa consents to Yosano transferring to the mafia.

Sky Casino Arc
Ōchi Fukuchi, commander of the Hunting Dogs, pays a visit to Fukuzawa while the President is in custody under Fukuchi's unit's supervision. The two men are childhood friends and Fukuchi brings some liquor to drink with Fukuzawa, joyfully chatting about their respective lives and responsibilities.

Fukuchi then sternly asks for Fukuzawa's confession in exchange for bringing a halt to the hunt for the Agency members. The President kindly refuses, and Fukuchi suddenly waves his blade only to stop an inch from cutting Fukuzawa's manacles. Indeed, Fukuzawa planned to free himself this way before taking Fukuchi's sword. The commander of the Hunting Dogs then praises the President's swordsmanship, wondering if someone who's able to draw a sword at the speed of sound like Fukuzawa is really human.

When the Hunting Dogs commander tries to bargain over information about Kunikida's whereabouts, Fukuzawa declines the deal once again: he deeply believes that Kunikida is still alive; otherwise he would have felt it. Fukuzawa also has absolute faith in every one of his subordinates and tells Fukuchi that as long one member remains, the Agency will never give up and is bound to win.

Kamui Revelation Arc
Fukuzawa is visited by Kamui and their companion, placing a hood over his head and escorting him out of his cell. Later, as the hood is removed, Fukuzawa finds himself and the other two on a rooftop. Thinking that they plan on silencing him by throwing him off the roof, Fukuzawa tells Kamui that he knows who they are.

On the rooftop, Ranpo reveals himself to Fukuzawa as the one wearing the gas mask. Ranpo tells Fukuzawa that he has successfully hijacked the assassination plots on the other Agency members, having brought Kunikida, Yosano, and Katai to safety. Though Fukuzawa becomes worried upon hearing that Ranpo has been shot during the hostage incident, Ranpo assures him that he merely made the police think he was shot, having escaped successfully by taking advantage of the confusion during first response. As Ranpo soon introduces Edgar Allan Poe as his collaborator throughout his rescue operation, he asks for Fukuzawa's next instruction, upon which the President orders Ranpo to crush the case once and for all, much to Ranpo's thrill.

Vampire Infection Outbreak Arc
Eventually, Fukuzawa and the others learn of Fukuchi's true identity and motive as Kamui, the Decay of Angels' leader. He then convenes with the rest of the rescued Agency members in Poe's novel-recreated Agency office at Ranpo's behest to discuss the erstwhile global conditions caused by the Decay of Angels. When Kyōka soon detectss some intruders with them, Demon Snow stabs through the table, under which Tanizaki and Kenji are hiding. Having invited back to rejoin the Agency by Mori himself, they are apparently planning to surprise them.

Fukuzawa soon initiates the meeting, and Ranpo briefs them how 16 armies have fallen due to Bram Stoker's ability, driving the remaining nations to panic and disorder. He informs them that the enemy aims not to ultimately stir the world into chaos but to acquire the mind-controlling ability weapon "One Order", which Fukuzawa explains to be very much like his own ability that lets a user command their subordinates without fail. Ranpo adds that Fukuchi can use One Order on the Humankind Army, therefore deducing that the Decay may be aiming for world domination. He then prepares the Agency to stop Fukuchi from acquiring One Order within 20 hours and readies to tell his strategy.