Sword of Esha'shama'im

From TCWiki

Massive magical sword of flamage once possessed by the Demon/Fallen Angel/On Heavenly Probation Esha'shama'im (Shama, for short.) Taken from him when he was defeated by Allanon Kisigar, Charles Embers, and Spike during his attempt to sacrifice Ash as part of a demonic wedding ceremony. Unbeknownst to any of them, Ash's soul (which she believes no longer exists) was bound into the sword. Only two people currently are aware of this, Mahou and Saeko.

The sword is five feet long, but shaped like a western style hand-and-a-half sword rather than a two-handed blade (it was made for an angel/demon, after all). When wielded by the right person the blade bursts into intense, white hot flame. Though it seldom does so, the fact it is possessed by Ash' soul means it is quite capable of talking (usually saying something snarky.)

In addition to containing Ash's soul, it also is inscribed with her True Name, which can be used to summon or control her as a demon.

Currently the sword is in the possession of Saeko, after she stole it from Charles Embers. Some would say that, should the sword fall into the wrong hands, it would be a Very Bad Thing. Others would say it already has.