Muroto Sumire is a highly accomplished researcher based at Magata Public University Hospital, where she also serves as the head of a legal medicine laboratory. She is recognized as one of the Four Sages, a group of elite scientists, and holds the responsibility of overseeing the New Human Creation Plan in Japan. Her work involves intensive study of the Gastrea, the parasitic monsters that threaten humanity, and she frequently provides technical advice and support to the protagonist, Rentaro Satomi, who is also her former student. Sumire possesses an extraordinary intellect and a deep knowledge of biology and medicine, which she applies to develop weapons and strategies against the Gastrea as well as to create the Cursed Children—artificially enhanced humans capable of fighting the monsters. Despite her brilliance, she exhibits a reclusive and eccentric lifestyle, rarely leaving her laboratory, and is often described as a hikikomori and a mad scientist. She has an easygoing and charismatic personality, but she also enjoys teasing Rentaro with playful pranks and bluntly pointing out his weaknesses. Her motivations are driven by a pragmatic desire to protect humanity, yet she is willing to make morally questionable decisions, including sacrificing the Cursed Children if it serves the greater good. This utilitarian mindset sometimes puts her at odds with Rentaro, who is more compassionate toward the children she created. Sumire maintains a professional working relationship with other key figures in the series, such as the Civil Security officers and government officials, though she generally prefers solitude. Throughout the story, her role remains that of a supporting scientist and strategist, providing crucial information and technological aid from behind the scenes. She does not experience major personal transformation during the anime, but her unwavering dedication to her research and her complex moral stance define her character. Notable abilities include her expertise in forensic medicine, Gastrea biology, and genetic engineering, as well as her capacity to analyze and devise effective countermeasures against new threats.