The Dying Yakuza Empire
Organization: Shie Hassaikai
Name Meaning: Eight Precepts of Death
Organization Type: Yakuza Crime Syndicate
Original Leader: The Boss (Name Unknown)
Acting Leader: Kai Chisaki (Overhaul)
Second-in-Command: Hari Kurono (Chronostasis)
Headquarters: Shie Hassaikai Compound, Japan
Affiliation: Japanese Criminal Underworld
Current Year: 2171
Status: Active — Operating in Secret
The Shie Hassaikai is an old Japanese Yakuza organization struggling to survive in an era dominated by professional heroes.
Once part of Japan's powerful criminal underworld, the organization declined as hero society expanded and traditional criminal syndicates lost their influence.
Under the leadership of Kai Chisaki, known as Overhaul, the Shie Hassaikai has begun transforming into a dangerous organization conducting illegal Quirk research and human experimentation.
Its ultimate objective is to restore the Yakuza's former power and reclaim control over Japan's criminal underworld.
However, the organization's greatest secret involves a young girl whose extraordinary Quirk could permanently alter the balance of power between heroes and villains.
Before the rise of modern hero society, Yakuza organizations controlled significant portions of Japan's criminal underworld.
These syndicates operated through strict hierarchies, territorial control, organized crime, and codes of loyalty.
However, the establishment of professional hero agencies gradually weakened their influence.
All Might's rise as the Symbol of Peace accelerated their decline, forcing many criminal organizations into hiding.
The Shie Hassaikai was among those affected.
Its elderly leader, known simply as the Boss, attempted to preserve the organization through traditional Yakuza principles.
He believed that even criminals required honor, loyalty, and a code of conduct.
However, his adopted protégé, Kai Chisaki, considered these traditions outdated.
Chisaki believed the Yakuza could only survive by acquiring a power capable of challenging modern hero society.
Quirk: Overhaul
Kai Chisaki is the acting leader of the Shie Hassaikai.
Taken in by the organization's original Boss as a child, Chisaki developed an intense sense of loyalty toward the man who raised him.
He became obsessed with restoring the organization to its former greatness.
His Quirk, Overhaul, allows him to disassemble and reconstruct anything he touches, including living organisms.
He can destroy objects instantly, reshape his surroundings, heal injuries, and manipulate biological structures.
Chisaki possesses an extreme aversion to germs and physical contamination, frequently wearing gloves and a plague doctor-style mask.
He considers Quirks a disease responsible for society's corruption.
Despite his stated devotion to the Boss, Chisaki's ruthless ambitions eventually drove him to betray his benefactor.
The original Boss strongly opposed Chisaki's increasingly violent methods.
When Chisaki proposed conducting experiments on the Boss's granddaughter, Eri, to develop weapons capable of destroying Quirks, the elderly leader refused.
He considered the experiments cruel and unacceptable.
Determined to proceed, Chisaki used his Quirk to place the Boss into a coma.
With the organization's rightful leader incapacitated, Chisaki assumed control.
He intends to restore the Shie Hassaikai's power before eventually awakening the Boss, believing his accomplishments will justify his actions.
However, many longtime members remain uncomfortable with Chisaki's leadership and his abandonment of their traditional principles.
Quirk: Rewind
Eri is the young granddaughter of the Shie Hassaikai's original Boss.
Her rare Quirk, Rewind, allows her to reverse the biological state of living organisms.
Because she cannot properly control her ability, its effects can be extremely dangerous.
After accidentally causing her father's disappearance through her Quirk, Eri was abandoned by her mother and placed in her grandfather's care.
Chisaki eventually discovered that Eri's abilities could potentially reverse the biological mechanisms responsible for Quirks.
He began conducting horrific experiments using her blood and cells.
Through his own Quirk, Chisaki could repeatedly disassemble and reconstruct her body, allowing him to continue the experiments.
Eri lives in constant fear, believing her existence brings suffering to others.
Her captivity remains one of the organization's most closely guarded secrets.
Chisaki's greatest ambition is the development of a drug capable of permanently destroying a person's Quirk.
Using biological material obtained from Eri, the Shie Hassaikai has begun manufacturing experimental ammunition capable of interfering with Quirk factors.
Early versions temporarily disable a victim's abilities.
Chisaki intends to perfect the formula, creating bullets capable of permanently erasing Quirks.
His plan involves selling these weapons to villains while eventually supplying a restorative serum to heroes.
By controlling both the destruction and restoration of Quirks, the Shie Hassaikai could establish an enormously profitable criminal monopoly.
Chisaki believes this would allow the Yakuza to reclaim its former position within Japanese society.
The Eight Bullets are the Shie Hassaikai's elite combat unit, consisting of dangerous criminals personally recruited to serve Overhaul.
Each possesses a specialized Quirk.
Shin Nemoto — Confession: Forces individuals to answer questions truthfully.
Rikiya Katsukame — Vitality Stealing: Absorbs stamina and vitality through physical contact.
Kendo Rappa — Strongarm: Enables devastating rapid-fire punches through extraordinary shoulder rotation.
Hekiji Tengai — Barrier: Generates powerful defensive barriers.
Toya Setsuno — Larceny: Allows him to steal objects from opponents through telekinetic manipulation.
Yu Hojo — Crystallize: Produces hard crystalline structures from his body.
Soramitsu Tabe — Food: Allows him to consume and digest nearly anything.
Deidoro Sakaki — Sloshed: Disorients nearby opponents, making them feel intoxicated.
Although dangerous individually, the Eight Bullets become especially effective when their abilities complement one another.
Their loyalty to Overhaul makes them willing to undertake dangerous assignments.
Two additional members hold important positions within the organization.
Hari Kurono — Chronostasis: Chisaki's closest associate and trusted lieutenant. His Quirk allows him to slow a target's movements after striking them with his specialized hair.
Joi Irinaka — Mimic: A senior member responsible for managing the organization's operations. His Quirk allows him to merge with and manipulate surrounding structures.
Both play important roles in protecting Chisaki and maintaining the organization's secret activities.
The Shie Hassaikai operates from a traditional Japanese compound concealing an extensive underground facility.
Beneath the property lies a network of corridors, chambers, laboratories, and concealed passages.
These areas provide secure locations for meetings, illegal research, and the containment of valuable subjects.
The underground complex is particularly dangerous because Mimic can manipulate portions of the structure, changing passageways and obstructing intruders.
The compound serves as both the organization's headquarters and the center of Chisaki's secret operations.
The Shie Hassaikai views professional heroes as one of the principal causes of the Yakuza's decline.
Chisaki believes the hero system has transformed criminals into powerless remnants of the past.
Rather than directly confronting Japan's strongest heroes, he intends to undermine their greatest advantage: their Quirks.
If his Quirk-erasing ammunition becomes commercially viable, even the most powerful Pro Heroes could become vulnerable.
The organization also maintains connections within the criminal underworld, allowing it to acquire resources, recruit dangerous individuals, and conceal its activities.
In 2171, the Shie Hassaikai remains an active but declining Yakuza organization.
Kai Chisaki secretly controls the syndicate while its rightful Boss remains unconscious.
The Eight Bullets serve as his primary enforcers, supported by Chronostasis and Mimic.
Beneath the organization's compound, Eri remains imprisoned while experimentation continues.
The Quirk-erasing drug project represents Chisaki's greatest opportunity to restore the Yakuza's power.
Although professional heroes and police remain vigilant toward organized crime, the true nature of the Shie Hassaikai's research remains undiscovered.
Chisaki believes that whoever controls Quirks controls the future of society.
And he intends to place that power in the hands of the Yakuza.
The old Yakuza empire is dying.
But Overhaul intends to resurrect it, regardless of the lives destroyed in the process.