Next was Tokugawa Ieyasu's father, who was assassinated by his henchman with the Muramasa Blade. Later on, Tokugawa Ieyasu cut his finger when he was young, and his wife was killed when he grew up. He went out to war and was ambushed by the Muramasa Blade.
It was said that it was done by the same Muramasa Blade.
The Muramasa Blade was like the curse of the Tokugawa clan, causing the family's four generations to bleed and die because of it.
Therefore, after the Tokugawa clan unified the Japanese, they treated Muramasa Blade as the Demon Blade and ordered the entire world to destroy the Muramasa Blades.
That was the origin of Demon Blade Muramasa.
Since the incident, in order to commemorate Tokugawa Ieyasu and the unity of the world that was hard to come by, the Tokugawa clan had put the Muramasa Blade, which had caused the blood of the four generations of the family, into the museum.