ONA
Description
Koku is a central character in the anime B: The Beginning. He lives a double life: by day, he works as a quiet and skilled violin craftsman under the employment of Lily Hoshina’s father, and by night, he operates as the vigilante known as Killer B, a name derived from the distinctive way he marks the number 13 at his murder scenes. Koku is a young man with heterochromia—his right eye is grayish-black while his left eye is dark teal—and long black hair. In his transformed state, which he can assume at will, he becomes a black-winged being with blue steel limbs, dark skin, and a more intricate eye pattern.
Koku was originally one of several genetically engineered children created at the Jaula Blanca Institute, an experimental facility that sought to develop beings with extraordinary powers. He was born with the ability to manipulate memories through both eyes, but his right eye was later removed and implanted into another subject, Minatsuki, for research purposes. At the institute, he formed a deep bond with a girl named Yuna, who became his closest companion and love interest. Their lives were shattered when Gilbert Ross orchestrated a brutal attack on the institute that killed many of the children and researchers, including Dr. Heath Flick, who had cared for them. Koku suppressed memories of the trauma, and the surviving children were scattered. For the next seven years, Koku dedicated himself to searching for Yuna, never believing she was dead.
In his everyday life, Koku appears quiet, polite, and reserved. He shows kindness through small gestures, such as bringing red bean buns to his employer’s family, and he is highly proficient at repairing violins, though he cannot play them himself. As Killer B, however, he becomes aggressive, ruthless, and single-minded. This side of him operates with cold precision, showing no mercy to enemies or even common criminals he deems obstacles. His dual personality reflects the unresolved pain of his past and his unwavering determination to reunite with Yuna.
Koku’s primary motivation is to find and rescue Yuna, whom he believes is still alive. He also seeks to uncover the truth behind the conspiracies surrounding Jaula Blanca and the shadowy organization known as the Market Maker, which controls the government of Cremona. His actions as Killer B are driven by these goals, targeting anyone connected to the events that destroyed his childhood.
Koku’s role in the story is that of a protagonist whose path intersects with Keith Flick, a genius detective of the Royal Investigation Service. Keith is investigating the Killer B murders, and through their encounters, Koku and Keith gradually become allies against the Market Maker. Koku’s most significant relationship is with Yuna; his search for her defines his entire journey. He also forms a connection with the Hoshina family, particularly Lily, though he keeps his true identity hidden from them. His adversaries include the members of Market Maker, such as the cold and calculating Minatsuki and the powerful Izanami.
Over the course of the series, Koku gradually recovers his suppressed memories and confronts the trauma of his past. He learns to control his abilities and accepts his identity as the Black-Winged King. His reunion with Yuna is a pivotal moment that restores his sense of purpose, and together they face the threats posed by Market Maker. In the second season, B: Succession, Koku continues to protect Yuna and fight against new challenges while deepening his understanding of his own nature.
Koku possesses a wide range of superhuman abilities. He can manipulate memories through his left eye, though he rarely uses this power due to a promise he made to Dr. Flick. He has superhuman speed and can move faster than the human eye can perceive, allowing him to dodge bullets and bypass security systems. He also demonstrates accelerated regeneration, healing from severe injuries, and a degree of immortality that grants him immunity to disease and apparent lack of aging. In his transformed state, he grows black wings that enable him to fly at great altitudes, and he can turn his left arm and left leg into blades of blue steel. These limbs, which he absorbed from the enhanced beings Kirisame and Izanami, are exceptionally durable and can cut through conventional materials. He can also absorb body parts from other superhumans to inherit their traits. In addition, Koku is skilled in disguise and infiltration, often using these talents to get close to his targets. Despite his formidable powers, he chooses to live a low-profile life as a craftsman, revealing his abilities only when necessary.
Koku was originally one of several genetically engineered children created at the Jaula Blanca Institute, an experimental facility that sought to develop beings with extraordinary powers. He was born with the ability to manipulate memories through both eyes, but his right eye was later removed and implanted into another subject, Minatsuki, for research purposes. At the institute, he formed a deep bond with a girl named Yuna, who became his closest companion and love interest. Their lives were shattered when Gilbert Ross orchestrated a brutal attack on the institute that killed many of the children and researchers, including Dr. Heath Flick, who had cared for them. Koku suppressed memories of the trauma, and the surviving children were scattered. For the next seven years, Koku dedicated himself to searching for Yuna, never believing she was dead.
In his everyday life, Koku appears quiet, polite, and reserved. He shows kindness through small gestures, such as bringing red bean buns to his employer’s family, and he is highly proficient at repairing violins, though he cannot play them himself. As Killer B, however, he becomes aggressive, ruthless, and single-minded. This side of him operates with cold precision, showing no mercy to enemies or even common criminals he deems obstacles. His dual personality reflects the unresolved pain of his past and his unwavering determination to reunite with Yuna.
Koku’s primary motivation is to find and rescue Yuna, whom he believes is still alive. He also seeks to uncover the truth behind the conspiracies surrounding Jaula Blanca and the shadowy organization known as the Market Maker, which controls the government of Cremona. His actions as Killer B are driven by these goals, targeting anyone connected to the events that destroyed his childhood.
Koku’s role in the story is that of a protagonist whose path intersects with Keith Flick, a genius detective of the Royal Investigation Service. Keith is investigating the Killer B murders, and through their encounters, Koku and Keith gradually become allies against the Market Maker. Koku’s most significant relationship is with Yuna; his search for her defines his entire journey. He also forms a connection with the Hoshina family, particularly Lily, though he keeps his true identity hidden from them. His adversaries include the members of Market Maker, such as the cold and calculating Minatsuki and the powerful Izanami.
Over the course of the series, Koku gradually recovers his suppressed memories and confronts the trauma of his past. He learns to control his abilities and accepts his identity as the Black-Winged King. His reunion with Yuna is a pivotal moment that restores his sense of purpose, and together they face the threats posed by Market Maker. In the second season, B: Succession, Koku continues to protect Yuna and fight against new challenges while deepening his understanding of his own nature.
Koku possesses a wide range of superhuman abilities. He can manipulate memories through his left eye, though he rarely uses this power due to a promise he made to Dr. Flick. He has superhuman speed and can move faster than the human eye can perceive, allowing him to dodge bullets and bypass security systems. He also demonstrates accelerated regeneration, healing from severe injuries, and a degree of immortality that grants him immunity to disease and apparent lack of aging. In his transformed state, he grows black wings that enable him to fly at great altitudes, and he can turn his left arm and left leg into blades of blue steel. These limbs, which he absorbed from the enhanced beings Kirisame and Izanami, are exceptionally durable and can cut through conventional materials. He can also absorb body parts from other superhumans to inherit their traits. In addition, Koku is skilled in disguise and infiltration, often using these talents to get close to his targets. Despite his formidable powers, he chooses to live a low-profile life as a craftsman, revealing his abilities only when necessary.