Born into the Shie Hassaikai, Chisaki was raised within the Yakuza under the mentorship of its elderly boss, whom he viewed as a father figure. As quirks became more prevalent and hero society rose to prominence, Chisaki grew increasingly bitter about the decline of the Yakuza and the societal shift toward heroes.

Obsessed with the idea that quirks were the root cause of society’s corruption, Chisaki sought to eliminate them entirely. His twisted logic led him to exploit Eri’s Quirk, Rewind, using her to develop Quirk-erasing bullets that he intended to sell to villains and later heroes, forcing society to rely on the Yakuza once again.

Chisaki is a tall, slender man with pale skin, short brown hair, and sharp golden eyes. He is usually seen wearing a green jacket with a fur-trimmed hood and a distinctive plague doctor mask, symbolizing his obsession with cleanliness and his Yakuza identity.

After his defeat and subsequent imprisonment, Chisaki’s appearance becomes more disheveled. He loses both of his arms due to Tomura Shigaraki’s punishment, leaving him severely weakened and reliant on others for survival.

Chisaki is methodical, intelligent, and deeply paranoid about germs and “uncleanliness,” which manifests in his obsessive-compulsive behavior. His cold and calculating nature allows him to manipulate others to achieve his goals, showing no hesitation in using Eri as a tool for his ambitions.

Despite his calm exterior, Chisaki harbors a deep resentment toward society and quirks, blaming them for the downfall of the Yakuza. He is fiercely loyal to the Shie Hassaikai’s traditions but is willing to use ruthless and unorthodox methods to restore the organization’s former glory.

• Shie Hassaikai Arc
  As the leader of the Shie Hassaikai, Chisaki orchestrates a plan to develop and distribute Quirk-erasing bullets. He exploits Eri’s Quirk, subjecting her to inhumane experiments to create the bullets. His confrontation with Izuku Midoriya, Mirio Togata, and the Pro Heroes culminates in his defeat and the liberation of Eri. Chisaki’s loss symbolizes the fall of the Shie Hassaikai, with most of its members arrested or incapacitated. His arms are destroyed by Tomura Shigaraki and Himiko Toga as punishment for his perceived arrogance, leaving him broken and powerless.

• Escape from Tartarus and Re-Arrest
  During the mass breakout at Tartarus caused by All For One, Chisaki is freed by Lady Nagant. However, his weakened state and lack of leadership render him ineffective. He is soon recaptured by Endeavor and returned to custody.