Ogai Mori leads the Port Mafia, having seized control by eliminating the previous boss eight years before the main story. This transition followed a failed suicide attempt by Osamu Dazai, who witnessed the event and was subsequently taken in as both patient and protégé. He possesses a tall, slender frame, straight black hair typically slicked back with two front bangs framing his face, and red eyes with patterned pupils. During Port Mafia operations, he wears a black pinstriped suit, white dress shirt, purple and white striped tie, black trousers, boots, a long black trench coat, maroon scarf, and white gloves. In public or while adopting his medical persona, he opts for a purple button-up shirt, black tie, black trousers, and a long white coat, wearing his hair loose. His personality is multifaceted. Outwardly, he appears as a clumsy, worried, ordinary middle-aged man—a deliberate facade. Beneath this lies a highly strategic mind, calm under pressure, capable of calculated cruelty and merciless action. He makes decisions based on logical assessments of the Port Mafia’s gains and losses, often prioritizing the organization over individual lives. This is exemplified by his manipulations that caused significant trauma to Akutagawa Ryunosuke and engineered the death of Osamu Dazai’s friend, Oda Sakunosuke—a move that eliminated a foreign threat while pushing Dazai toward defection. His philosophy holds that a leader is both ruler and slave to the organization, obligated to ensure its survival and prosperity through any means necessary, however morally reprehensible. He maintains a polite, gentlemanly demeanor that can shift into intense intimidation. He grants capable subordinates a degree of autonomy but demands results and effort, as seen in his tolerance of Akutagawa’s behavior. He retains deep respect for his predecessor, despite having killed him, and views unnecessary loss of subordinates as a leadership failure. His primary motivation is maintaining Yokohama’s balance of power. He believes his ruthless control of the Port Mafia prevents more destructive forces from seizing power and plunging the city into chaos—a purpose acknowledged by Fukuzawa, leader of the Armed Detective Agency, as part of an agreement to uphold a tripartite framework for the city’s stability. He possesses the supernatural ability Vita Sexualis, which allows him to summon and fully configure an entity named Elise, who typically manifests as a young girl. He controls her personality, actions, and capabilities, enabling her to levitate, attack with large medical equipment, or defend at high speeds. The ability consumes energy to maintain, and if dispelled, requires time to resummon. Elise’s defiant personality was consciously configured to mimic a younger version of his former protégé, Akiko Yosano, reflecting a particular obsession. His history includes service as a military physician for the infantry fourteen years prior, during the Great War. There, he recruited the eleven-year-old Akiko Yosano to use her healing ability on the battlefield, employing methods that resulted in her severe mental breakdown from trauma. His relationship with Osamu Dazai is particularly significant. He recognized Dazai’s intelligence but also perceived him as a threat. The manipulation leading to Oda Sakunosuke’s death was designed to remove Mimic while driving Dazai to leave the Port Mafia. This exile was also intended to allow Dazai to learn about protecting others from the Armed Detective Agency, grooming him as a successor who understands both light and darkness, thereby ensuring Yokohama’s future stability. He maintains a working relationship with executive Ozaki Kouyou, who offers dry criticism but remains loyal, recognizing his leadership as preferable to the previous boss’s destructive tendencies. He agreed to her request to spare the defecting member Kyoka Izumi. Outside his strategic persona, he displays a doting, nearly obsessive attitude toward Elise, spending excessive time and resources dressing her and indulging her whims—behavior she often finds irritating. This, along with his configuration of Elise as a young girl, is a noted trait that disturbs other characters.