TV-Series
Description
Mayuri Kurotsuchi is the captain of the 12th Division of the Gotei 13 and the second president of the Shinigami Research Institute. He is one of the most intellectually gifted and morally ambiguous figures in the Soul Society. His background begins over a century before the main storyline, when he was an inmate in the Maggots Nest, a detention facility for souls deemed too dangerous for ordinary society. He was considered the most threatening prisoner there, kept chained for his utter disregard for life when conducting experiments. His circumstances changed when Kisuke Urahara, then captain of the 12th Division, visited him and offered him a position in the newly formed Shinigami Research Institute. Mayuri initially refused, not wanting to be an assistant, but accepted when Urahara promised that Mayuri would succeed him if anything happened. After Urahara was forced to leave the Soul Society, Mayuri became captain.

Personality wise, Mayuri embodies the archetype of the mad scientist. He is sadistic, cruel, and views all living beings, including his own subordinates and enemies, as nothing more than experimental subjects. He feels no remorse for the pain or death he causes, and his curiosity is the only force that drives him. His appearance is deliberately theatrical and unsettling; he paints his face with black and white makeup to resemble a skull, and his captain's uniform is always topped with an extravagant headpiece that changes with each story arc. Underneath the makeup, his natural features reveal blue hair, yellow eyes, and tubes in place of ears, a result of his own bodily modifications. He possesses a sharp, mocking sense of humor and a deep disdain for rivals such as Kisuke Urahara, whom he resents for being considered the greater scientist.

His primary motivation is the relentless pursuit of knowledge and scientific advancement. He values discovery, adaptation, and evolution above all else, and he explicitly rejects the concept of perfection, arguing that a true scientist should never strive for a static, perfect state because that would end progress. This philosophy is central to his identity and is most clearly stated during his victory over Szayelaporro Granz. Despite his amorality, he does possess a form of pride in his creations, particularly his artificial daughter and lieutenant, Nemu Kurotsuchi. While he initially treated Nemu with cold indifference, her self-sacrifice during the battle against Pernida Parnkgjas provoked a rare display of distress and led him to preserve her brain to ensure the enemy's defeat. In the epilogue, he created a new artificial daughter named Nemuri Hachigo.

In the story, Mayuri first appears as an antagonist during the Soul Society invasion arc, hunting down the intruders. He tortures and kills his own subordinates without hesitation to trap Uryu Ishida and Orihime Inoue. His battle with Uryu is brutal, and he reveals that he experimented on Uryu's grandfather, Soken Ishida, purely out of scientific curiosity. After his defeat, he escapes by liquefying his body. He later becomes a crucial ally in the Hueco Mundo arc, where he saves Uryu and Renji Abarai from Szayelaporro Granz. Using a bacterium he had previously planted in Uryu's body, he had already analyzed the Arrancar's abilities and systematically dismantled him. During the Thousand-Year Blood War arc, Mayuri plays a pivotal role. He devises countermeasures against the Wandenreich's ability to steal Bankai, resurrects and controls a squad of Arrancars as his personal army, develops a serum to override Giselle Gewelle's zombie control, and faces Pernida Parnkgjas, the left arm of the Soul King. His victory over Pernida costs Nemu her life, but he ultimately destroys the entity using her modified cellular structure.

Key relationships define his character arc. His bond with Nemu is the most significant, evolving from cold utility to something resembling paternal pride, though it remains framed within his scientific perspective. His relationship with Kisuke Urahara is one of rivalry and envy; he constantly seeks to prove that he can surpass or replicate Urahara's inventions. He holds no respect for his fellow captains and often clashes with Kenpachi Zaraki and others, but he is tolerated because his contributions to the Soul Society's defense are indispensable. His conflict with Uryu Ishida stems from his past experiments on Quincies, and with Szayelaporro Granz, it is a clash of scientific philosophies, with Mayuri demonstrating that adaptation and imperfection are superior to the Arrancar's self-proclaimed perfection.

Development in Mayuri is subtle but present. While he never becomes a conventionally good person, his later actions show a grudging investment in the survival of his allies and a deeper emotional reaction to the loss of Nemu. He becomes more willing to cooperate with others, though he maintains his condescension and manipulative methods.

His abilities are vast and unconventional. His greatest asset is his scientific intellect, allowing him to think many steps ahead, analyze opponents, and create tailored countermeasures. He has extensively modified his own body, implanting hidden weapons, extra organs, and a liquid form that allows him to escape death. He is a master of kido and possesses immense spiritual pressure. His Zanpakuto is Ashisogi Jizo, which in its shikai form takes on a deformed trident appearance. When it stabs an opponent, it severs the nerve signals controlling limb movement, causing paralysis while preserving the ability to feel pain. His bankai, Konjiki Ashisogi Jizo, manifests as a giant caterpillar with a baby's head and a silver halo. It releases a lethal poison created from Mayuri's own blood, which is deadly to anyone except Mayuri and Nemu. The bankai can also extend numerous blades from its chest and can be modified by Mayuri. He regularly changes the poison formula so that past data is useless. Against Pernida, he unveiled a further modification, Konjiki Ashisogi Jizo: Makai Fukuin Shōtai, an enormous infantile form that can generate new bodies adapted to counter the enemy's abilities, such as developing seventy thousand layers of nerves to resist Pernida's power. Beyond his Zanpakuto, Mayuri employs a vast array of drugs and devices, including a superhuman drug that accelerates perception to the point of paralysis, a precognition drug that traps enemies in mental time loops, blood-altering serums to control zombies, and boots that replicate the Quincy technique Hirenkyaku for flight. He created the artificial Shinigami technology used to produce Nemu and is capable of reviving and modifying Arrancars.