Koizumi

No specific details about Koizumi's physical appearance are provided.

He is referred to as an elderly man, with suggestions of vitality due to his numerous relationships with younger women.

Koizumi is shrewd, calculating, and commands respect tinged with fear.

He is pragmatic, ruthless in climbing and maintaining power, and places personal ambition above loyalty.

Despite his grandeur, he is isolated, struggling with his family and driven by self-interest.

While he has moments of regret and support, his empathy is often eclipsed by opportunism.

Koizumi was the central figure in a powerful Tokyo political faction known simply as “Tokyo.”

He served as a high-ranking officer, likely a colonel, in the pre-war Japanese military.

His connections spanned across politics, business, and the military, enabling him to exert immense influence.

He befriended Hifumi Takano during their military days, and this bond would shape many lives.

Despite supporting Hifumi’s research on the Himamizawa Syndrome, Koizumi prioritized political image, even abandoning his friend under pressure.

After Hifumi's death, he extended support to Miyo Takano, Hifumi’s adoptive daughter, seeing strategic value in her ambitions.

Koizumi died from acute myocardial infarction at the height of the Himamizawa Syndrome research.

Koizumi’s greatest power lies in his formidable political and financial influence.

He could open doors, allocate enormous budgets, and override the objections of other elites at will.

Strategic manipulation and bribery were his standard tools, enabling projects such as the Irie Institute and the entire Alphabet Project.

He was feared for his reach, even after death, as institutions crumbled without his backing.

Hifumi Takano: Close wartime friend, shared a deep connection as part of the same military unit. Koizumi aided his research until political calculations forced him to withdraw support.

Miyo Takano: Hifumi’s adoptive daughter. Koizumi became her powerful patron, giving her ten billion yen and supporting her research. Their relationship was complex—he was both a benefactor and an enabler of her darker ambitions.

Other Politicians and Subordinates: He commanded a massive network, often overriding opposition. His death immediately triggered backlash and dismantling of everything he built.

His Family: His family ties were strained, possibly due to his own infidelity and neglect, leading to a cold and distant household.

Young Women: Even in old age, Koizumi maintained numerous romantic affairs, further straining his family relationships.

His name was inspired by Junichiro Koizumi, the then-Prime Minister of Japan, at the time the work was published.

In the anime, he is voiced by Tsubasa Shioya, and is posthumously revealed as a legendary power broker whose absence unravels Tokyo’s shadow government.

He is the founder of the Alphabet Project and the Irie Institute.

He was involved in the infamous Lowell Scandal, where dangerous drugs were illicitly approved for testing and sale.

Despite patriotic speeches, Koizumi permitted foreign companies to use Japanese citizens as test subjects, prioritizing bribes and influence over genuine national welfare.

No explicit quotes are provided in the original text.

Koizumi is often addressed as “Colonel” by Hifumi Takano, a sign of mutual respect and shared history.

The Rise of a Fixer

Koizumi comes into prominence as the central figure of the clandestine group, Tokyo, using shrewd political maneuvering to shape the direction of postwar Japan.

He forges a bond with military doctor Hifumi Takano, supporting his medical research into a mysterious local disease, the Himamizawa Syndrome.

The Himamizawa Syndrome and Betrayal

As Hifumi’s research makes headway, Koizumi faces a political dilemma.

During the Marco Polo Bridge Incident, soldiers from Himamizawa are implicated in a shooting, and Koizumi fears the societal chaos exposure would bring.

Under international and domestic pressure, he abruptly abandons Hifumi, forcing him to halt the research to protect Japan’s reputation and history.

Legacy and Manipulation

Wracked with some regret but more driven by calculation, Koizumi later takes Hifumi’s adoptive daughter, Miyo Takano, under his wing.

He becomes instrumental in her ambitious investigations, financing her with ten billion yen.

She uses this immense sum to recruit the Yamainu, a shadowy force that will later play a devastating role in carrying out catastrophic endgame strategies.

Scandal and Corruption

Koizumi’s thirst for influence leads him to approve hazardous drugs, resulting in the Lowell Scandal: a pharmaceutical disaster where foreign companies tested unapproved medication on Japanese patients.

His bribes and political interference enable the cover-up, but tragedy follows as mental health patients commit suicide, forcing a nationwide reckoning and resignations across the government and pharmaceutical sectors.

Despite supposedly acting for Japan, Koizumi repeatedly undermines his country’s welfare for personal power and profit.

Downfall

Koizumi’s sudden death from a heart attack marks the end of an era; his vast political machine quickly disintegrates.

Research projects he once bolstered are abandoned by opportunistic subordinates, including everything Miyo Takano has accomplished, leaving her vulnerable.

All his alliances prove shallow—he is ultimately remembered more for his many misdeeds than any good intentions.

Koizumi is not truly a villain by intention, but his decisions create cascading tragedies for both individuals and the nation.

His story is a cautionary tale of unchecked power, political ambition, and the personal losses hidden behind masks of authority.