The Zanpakutō's form is that of a straight-bladed katana. The tsuba is in the shape of a cat's head, with two triangles on the top half curving into ear-points and the bottom half tapering down into a single point. It has a dark red handle.
- Shikai: Its release command is "Growl" (唸れ, unare).
Shikai Special Ability: In its Shikai, Haineko's blade turns to ash, and with a flick of the hilt, she can cut anywhere the ash has landed on. All the ash that surrounds opponent(s) might as well be the sword. With simple hand gestures and a thought wielder can control where the ash goes as well as make it take various forms. Haineko is very hard to fight against. The main attack strength of Haineko comes from how much ash makes contact, thus why it is clumped together. If the ash was to attack the opponent in single particles, the damage would be little to nothing. The ash can cut through objects as easily as a sword would. Haineko can be a defensive weapon as well by having it take the form of a shield to defend against attacks. This katana is incredibly difficult to use due to the moody, lazy, and self-centered nature of Haineko.