Nemu is the lieutenant of the 12th Division in the Gotei 13, serving under Captain Mayuri Kurotsuchi. She is an artificially created being, combining her father's research into artificial bodies and souls. This background has made Nemu introverted and melancholic, often choosing to remain silent in her captain's presence. Her relationship with Mayuri is far from conventional; he shows little concern for her well-being, frequently using her as bait in combat. The most one can say in his favor is that he occasionally expresses pride in his skill as her creator when her life is at stake. Despite enduring constant abuse and mistreatment, Nemu remains fiercely loyal to Mayuri and has expressed worry about the possibility of his death, likely due to her gratitude for him bringing her into existence.
Unlike her father, Nemu displays compassion towards others, such as when she saved Uryū Ishida's life as a gesture of thanks for not killing Mayuri. Based on the ending segments of the 13 Squad episodes and the Bount arc, Nemu's fighting style incorporates capoeira-like martial arts and kido spells. Her body is designed to withstand fatal injuries, though she still feels pain. This resilience allowed her to survive being used as a host by Szayel Aporro Granz, who intended to revive himself while leaving her as an empty shell. Mayuri can quickly repair her in such situations, enabling her to continue following his orders. Nemu is immune to Mayuri's poisons but carries various antidotes and toxins derived from his research within her own body, making her highly dangerous to anyone who attacks her internally.
Although Nemu does not typically carry a zanpakutō, it is revealed in an illustration from the artbook "All Colour but the Black" that she possesses one. Her zanpakutō takes the form of what appears to be a thin katana.
