Burando Ayame practiced traditional Japanese medicine before abandoning it as ineffective. He stowed away on a foreign vessel to master Western medicine, returning to Japan after seven years. This illegal departure breached shogunate edicts, leading to his imprisonment. Kagimura Habaki, commander of the Shogun's Banshu samurai, identified Burando's expertise in Western science and enlisted him to uncover immortality's secrets. Habaki assigned Burando and another doctor, Mouzen, to conduct experiments on Manji, an immortal condemned prisoner, demanding results within fourteen days.

Burando focused on Manji's regenerative abilities, driven by parasitic bloodworms known as kessen-chu. He traced their origin to specialized tissue clusters, called kessen-ki or kessen-bases, embedded throughout Manji's body. These kessen-bases generated the bloodworms to repair injuries, including damage to themselves. Burando documented the limits of this immortality: the kessen-chu could not heal injuries predating their implantation and could be overwhelmed by catastrophic damage, destruction of all vital organs, prolonged starvation, asphyxiation, or extreme temperatures. He noted severed limbs regenerated slower than wounds near kessen-ki clusters and that the bloodworms perished outside a host body.

Under Habaki's intense pressure, Burando discarded medical ethics. He performed brutal experiments, transplanting Manji's limbs onto other prisoners to test regeneration compatibility and blood rejection, resulting in numerous deaths. The bodies were disposed of in mass graves. His actions inadvertently aided Rin Asano in locating Manji within Edo Castle's dungeons.

Burando's meticulous research notes survived him. Generations later, his great-great-granddaughter, Ayame Buran, inherited his work. She became a researcher obsessed with Manji's immortality, declaring her intent to conceive a child with him to investigate potential hereditary transmission of the bloodworms.