Bakuzan

The Secret Sword Bakuzan (秘剣縛斬) is a special sword used by Satsuki Kiryūin with the ability to cut Life Fibers. It was split into Bakuzan Gako and Bakuzan Kōryū after Satsuki was defeated by Ragyō Kiryūin. After being broken, it was later revealed that the two halves of the sword can mimic the Scissor Swords' ability to nullify Life Fibers regeneration.

Secret Sword Bakuzan
Satsuki Kiryūin owns Secret Sword Bakuzan, a black bladed katana. It is very powerful, able to fight evenly with the Scissor Blade.

Bakuzan Gako
The Bakuzan Gako (縛斬・餓虎) is a small dagger wielded by Nonon Jakuzure. She gave it back to Satsuki after rescuing her.

Bakuzan Kōryū
The Bakuzan Kōryū (縛斬・蛟龍) is larger than the Bakuzan Gako, having been reforged as a short sword. It is wielded by Ira Gamagōri at first, and is later given to Uzu Sanageyama. As Gamagōri states, it is "more [his] thing". Sanageyama gave it back to Satsuki after she was rescued.

Trivia

 * Satsuki's false toenails are made of the same material as the Bakuzan.
 * Ira Gamagori's final Goku Uniform's plating is as strong as Bakuzan.