|Literal Meaning:||Flying Thunder God|
|Weapon type:||Katana, Black Sword|
Hiraishin is a Katana with black tsuka ito weave with a ornate silver same under the cord, and a Gold kashira. It has a black tsuba and The blade itself is pitch-black with a very strong purple sheen hence it is a "Black Sword" (黒刀 Kokutō?) and it has runic markings running across the blade; the scabbard is dark blue and has a bronze tip that matches the kashira.
Not much is known about the Katana, however it was Strong Enough to withstand a Punch From "Diamond" Jozu with no damage done to it.