The sword is sealed as a rather ordinary-looking katana with a uniform curved blade. However, the tsuba and end of the hilt are yellow, while the handle is blue.
When the command "Unlock" is said, the sword glows and transforms into a very large key the size of a sword.
The key weapon has no edge, but is powerful enough to dent armor when swung or thrust. But the key has five key abilities that give it an edge over even a captain.
- Portal Door: At the command "Open", a door opens in midair that the user and the user alone can enter. They can then exit elsewhere in the area, even in midair, through another door. The "door" looks as if a circle has been cut out of the scenery and opens on invisible hinges. The door actually gives the user access to a dimension where they can hide and either plan a strategy or recover. By moving elsewhere in the dimension and summoning another door, it looks as if they can teleport using the doors.
- Bankai Lock: After the command "Seal" is said, the Zanpakutou shoots a beam of light from the tip. When the beam hits the opponent, they are rendered unable to use their Bankai. This allows the Shinigami to fight evenly against even a Captain. However, the beam can be dodged if the opponent is able to react quick enough.
- Clear Light: At the command "Purify", the user can stab the end of the key into the ground to release a circle with an intricate pattern on the ground, enveloping the surrounding area in light. This heals any and all negative conditions placed on the user or the area that the ability is used. So if the opponent had managed to crack the floor, the circle of light will repair the damaged floor as long as it is within the circle. Or if the opponent has covered the ground in lava or surrounded the area in a raging inferno, the ability will restore the ground within the circle to it's original state, or create an area where the inferno will not burn. The size of how far the circle stretches depends on how much Reiryoku the user puts into it, but it takes a great deal of Reiryoku to cover a large area. If the user is poisoned, Clear Light will remove the poison. The same goes for burns and frostbite. Using Clear Light to heal a negative condition will also make the user immune to it for about ten minutes, but this immunity will only occur if Clear Light is used to heal the condition, so it cannot be used at the start of a battle to prevent the condition from ever being placed. However, Clear Light will not heal injuries. Only negative effects on the user or the area.
- Relay: At the command "Relay", the effects of Kido and healing will be spread across an area, allowing the user to heal everyone present (including themself) with a healing Kido or healing ability. The same goes for other Kido and abilities that bestow a positive effect.
- Weapon Recall: A rather unique ability of Kagiyaiba is that if the Zanpakutou is ever knocked out of the user's hands, they can hold out their hand and call it back to them. The Zanpakutou will vanish in a flash of light and re-materialize in the user's outstretched hand. It does not require a command word, so it is great for surprising the opponent and making sure one is able to defend themself at all times.
The Zanpakutou's spirit takes the form of a treasure chest with ten locks sealing it shut. The spirit's voice comes from inside the chest, which rattles as if what is inside is struggling to get out. It would seem that either the spirit is inside the chest, or it is the chest.