Kuroboshi

Kuroboshi (黒星, literally meaning "Black Star") is the signature sword of the samurai, Takeshi. Named by Takeshi in honour of his master's own sword, Kurosawa, while at the same time referencing the blade's appearance and special ability. Kuroboshi has a similar design as Kurosawa, being fairly long and thin with a rectangular guard, a difference lies in the actual blade, Kuroboshi's blade is black and made from a meteorite. Takeshi is able to use radiation from the meteorite to enhance his chakra to monstrous levels, he discovered this upon studying ninja villages and coming across Hoshigakure and their Star Training. Other than this the blade functions exactly the same as any other. Takeshi uses Kuroboshi primarily in Iaidō.