If a Bushi commits Seppuku and is accepted by Fudo Myo-o, their body will transform into two objects; a Key (鍵,Kagi?) and a Soul (魂,Tamashii?). After that, the Key and the Soul are spontaneously assembled from the Locker Ball. The Locker Ball forms a new robotic body and a new Samurai is born with a Threefold Body.
The Samurai Key represents a rope that binds (繋ぐ,Tsunagu?, lit. to tie/connect) one object to another, the opposite to a Samurai Soul (侍魂,Samurai Soul?), which represents a rod that splits (断つ,Tatsu?, lit. to cut off) objects in two.
Abilities and Powers
Samurai Key has an Artificial Intelligence and can be used to show a holographic pannel to show information. In contact with another person, the Samurai can read your mind to get data and hack another Samurai Key.
Samurai Keys can download a License (免許,Menkyo?, lit. licence/permit/certificate) of one the Four Schools to gain information and learn skills and techniques. However, some keys are not able to download a license, an example being Benkei. There is also a special License called Full Master License (免許皆伝,Menkyo Kaiten?, lit. possessing full mastery of an art/full mastership) exclusive to the heads of each schools.
Samurai can also connect their Key to another Samurai's Key. This allows them to connect their minds to communicate and exchange knowledge. Through such connections, a Samurai with a license can enable one without a license to use techniques by having them trace their movements.