Summary
Masamune is the demon blade and Tsubaki's older brother, a highly perilous weapon that roams the world by possessing hosts to fulfill his desire to collect any soul he chooses. He communicates using archaic language and has a penchant for composing haiku. His strategy involves exploiting the fears of others to possess and control them until he completely takes over their souls. Masamune adheres to a survivalist philosophy where only the strong endure, while the weak exist solely to serve them. This worldview crystallized when Tsubaki inherited the family's multiple weapon forms, a decision that led him to believe he was more deserving of that power than his sister. Eventually, he allows Tsubaki to defeat and absorb him after recognizing her genuine care for him. This event grants her his katana form and all his abilities, marking the first time she successfully absorbs a soul. He now resides deep within Tsubaki, manifesting as a large deer. Masamune cannot perform attacks unless he has possessed someone to wield him. His Soul Possession technique allows demon blades to overpower and control their user's soul. He utilizes Shadow Puppet to manipulate the shadow of his possessed host for pincer attacks, though the puppet can only say shadow. By folding the Shadow Puppet onto the blade, he executes Puppet Strike, creating a long-reaching lunge thrust. Following this, Split Branches causes large spikes to emerge from the shadow's body to skewer enemies at close range. Finally, Puppet's Rain involves using multiple Shadow Puppets to restrain an opponent before Masamune stabs them.
