Kokutō

The is a unique sword wielded by Raidō Namiashi. The blade is a katana with a darkened, non-reflective surface. He used it in conjunction with Aoba's Scattering Thousand Crows Technique to conceal himself and the blade and successfully fend off Akatsuki member Kakuzu.

Trivia

 * It is unknown whether or not this sword has any special powers, but it is the only sword of its kind seen in the series thus far. Therefore it can be called unique regardless of whether or not it has any ability other than blending with the Scattering Thousand Crows Technique.