Athamé (血呼刀, Asame, lit. "Blood Calling Blade") is the primary weapon of a Vesper. Its primary uses are to channel and direct spiritual energy, which can be used to create Purification Circles and perform exorcisms. It is a manifestation of one's spiritual energy. Although it is named for the Athamé blade, the weapon can take almost any form, from a knife or a gun to a credit card. Irin wield a similar weapon called a Godsword.
Irin have always carried Athamé as a means to dispatch souls. The Athamé purifies the soul of evil influences and allows it to transmigrate to its next life.
The most basic form of an Athamé is a small, short blade. It is frequently disguised as a small personal effect that has sentimental meaning to the owner, such as a necklace, talisman, or omamori. Fuyuki Hibari's Athamé came from an omamori given to him by his father; Hanata Hibari's was his bokuto from his kendo days.
An Athamé is a manifestation of the wielder's spirit. Thus it can be a longsword, gun, or other weapon which best suits its wielder. They can change size and shape at any time, depending on the user. It can be anything from a a knife to a credit card. They are usually small and concealable.
The Athamé is a materialization of the Shigyoku, and as such, it reflects the spiritual condition of its master. For Vespers, this is threefold; the Athamé reflects the will and powers of both its master and its Corona, as well as any other souls that were used to create it. As a result, the Athamé of Vespers and Ochigami are corrupted and have a craving for blood.
The weapons of Ochigami and Vespers are fundamentally different.
Due to its use as a high-energy channeling device, Athamé are much more powerful than they appear. It is the primary weapon of the Irin as well as their Vesper descendents, and they can even be used by humans with some ability of ESP to purify an area. Its ability to channel and direct spiritual energy is used for three main purposes:
The Shigyoku is mineralized spirit matter and cannot be destroyed by mere power. Only an Athamé can purify a Shigyoku. However, it must be noted that an Athamé cannot purify itself; that is, it cannot be used to purify or break one's own Shigyoku.
An Athame is never to be used to draw blood. It is only meant to purify spiritual matter. Consequently, Vespers and those with corrupted Athame are breaking the rules of the Athame themselves.
Corrupted Athame are those wielded by users with disturbed souls, including all Vespers and Fallen Angels.