Hari Kurono functions as underboss assistant in the Shie Hassaikai yakuza organization under Kai Chisaki (Overhaul). Their childhood association forms the bedrock of Kurono's unwavering loyalty. As a veteran member, he shoulders significant responsibility as Chisaki's trusted confidant and enforcer, uniquely permitted to address the leader informally as "Kai." He oversees critical operations, particularly safeguarding the Quirk-Destroying Drug serum. Kurono possesses a distinctive appearance: pale silver chin-length hair styled into sharp "clock needles" manifesting his Quirk, fair complexion, thin dark eyes, and pointed eyebrows creating a severe countenance. During operations, he consistently wears a black plague mask with gold trim and circular glasses, paired with a long white raincoat featuring an upright hood, crafting an imposing silhouette among the Eight Bullets. His personality exhibits calculated detachment and ruthless pragmatism. He maintains composure witnessing Chisaki eliminate subordinates or subject Eri to experimentation. Kurono's subservient dedication prioritizes Chisaki's ambitions above ethics, manifesting in covertly healing the leader's injuries and eliminating threats. Occasional protective concern for Chisaki surfaces in combat. Analysis suggests his unquestioning obedience may have facilitated Chisaki's descent into extremism. Kurono's primary ability is the Quirk "Chronostasis," extending hair as needle-like projections. The shorter front strand immobilizes targets for one minute; the longer rear strand induces one-hour paralysis, drastically reducing motor function. Absolute physical stillness remains critical during hair extension. He demonstrates proficiency with a customized dart-firing handgun, carries a concealed knife, and exhibits tactical intelligence by analyzing opponents' weaknesses mid-battle against adversaries like Mirio Togata and Eraser Head. During the Shie Hassaikai raid, Kurono aided Chisaki's escape with Eri through labyrinthine corridors. Confronted by Mirio Togata, he employed gunfire but was swiftly overpowered and rendered unconscious. Upon awakening amid pro heroes' arrival, he ambushed Shota Aizawa (Eraser Head), immobilizing him with Chronostasis and blindfolding him to neutralize his Quirk-erasing ability. During Kurono's attempted execution of Aizawa, Tamaki Amajiki (Suneater) intercepted and captured him. Post-raid, following Chisaki's defeat, Kurono was incarcerated separately from Tartarus. His relationships center overwhelmingly on Chisaki, whom he supports without moral reservation as physical protector and strategic advisor. Kurono views Chisaki's vision as worthy of absolute dedication. His interactions with Eri involve complicity in her suffering, yet include moments of non-fearful physical contact like hugging, contrasting with her terror toward Chisaki, rendering their dynamic ambiguous. Additional designations include the villain alias "Chronostasis" and the epithet "The Time Master Inviting You to a Prison of Time." He participates in key battles against the League of Villains and U.A. heroes during the Shie Hassaikai conflict.