Akemura Soga—known as the legendary "Sword Master" (or *Kensei*)—is one of the most pivotal and formidable figures in *Kagurabachi* lore. As the brother-in-law and closest ally of master blacksmith Kunishige Rokuhira, Soga was entrusted with Magatsumi (commonly known as *Shinuchi*, meaning "masterpiece"), the sixth and most powerful of the seven Enchanted Blades. Forged from Datenseki during the devastating Seitei War, Magatsumi acts as the linchpin of the Enchanted Blades' Lifelong Contract system, tying the life force of the other blade bearers directly to Soga's own survival. Though celebrated as the war hero who saved Japan, Soga's extreme ideals eventually led him to unleash the blade's horrific true potential, turning a peace treaty into an unprecedented tragedy.
In battle, Magatsumi manifests the wielder's spirit energy into lethal, nature-themed sorcery characterized by darkening ground, lethal fields of blooming flowers, and shadowy insect constructs such as butterflies, centipedes, and dragonflies. The blade grants enhanced vitality by draining the life force of nearby enemies and environment through its floral fields. Uniquely, Magatsumi can bypass standard contract constraints, allowing Soga to possess proxy wielders or project his spirit energy remotely. Magatsumi's most devastating technique, Malediction (*Kodoku*), drastically amplifies its vitality absorption on a catastrophic scale—a power Soga used to single-handedly eradicate roughly 200,000 islanders, cementing Magatsumi as the most dangerous weapon in *Kagurabachi*.