Mayuri Kurotsuchi commands the 12th Division and the Soul Reapers’ Research Institute, a role secured after his release from the Maggot’s Nest, where he was imprisoned a century earlier for unethical experiments. Recruited by Kisuke Urahara as vice-president of the institute in exchange for scientific freedom, he seized the captaincy following Urahara’s exile. His crowning achievement, the Nemuri Project, birthed the artificial soul Nemu Kurotsuchi on its seventh iteration, appointing her as his lieutenant. Adorned in grotesque face paint and flamboyant attire evoking a distorted homage to Marilyn Manson, his deliberately inhuman aesthetic underscores his disdain for conformity and desire to unsettle. A quintessential mad scientist, he treats all life—subordinates included—as expendable test subjects, exemplified by implanting explosives in allies during the Ryoka invasion and weaponizing Nemu in combat. His Zanpakutō, Ashisogi Jizō, paralyzes foes by severing nerves, while its Bankai form, Konjiki Ashisogi Jizō, spews lethal blood-based toxins. He engineered the blade to self-destruct if hijacked and tailored variants like the Makai Fukuin Shōtai to counter specific enemies, such as Pernida Parnkgjas. Body modifications, including liquefaction to escape fatal wounds, further exemplify his experimental ethos. During the Soul Society arc, he battled Uryū Ishida, taunting him with his role in Soken Ishida’s torture and death. Though forced to retreat by Uryū’s Quincy powers, his tactical ruthlessness left a lasting mark. In Hueco Mundo, he outmaneuvered Espada Szayelaporro Granz using a perception-altering drug, mocking the Arrancar’s pursuit of perfection. The Thousand-Year Blood War saw him sanction the slaughter of 28,000 Rukon residents to restore soul equilibrium and collaborate with Urahara on Hollow-based countermeasures against Quincy medallions. He deployed zombified allies like Toshiro Hitsugaya via control serums and revived Arrancars as tactical pawns. Against Pernida, Nemu’s sacrificial act unveiled a rare flicker of paternal concern; he preserved her brain to ensure the enemy’s defeat before creating her successor, Nemuri Hachigō. His dynamic with Nemu oscillated between scorn and veiled pride, with flashbacks hinting at paternal investment masked by scientific ambition. A bitter rivalry with Urahara fueled resentment over intellectual comparisons, often provoking violent outbursts. Spin-offs like *Bleach: Fade to Black* highlighted his chaotic laboratory experiments, including incidents where unstable inventions jeopardized the Soul Society, cementing his reputation as a volatile yet indispensable asset to the Gotei 13.