MitMor

Mitmor amulets, or sacred knives have been created in Thailand for hundreds of years and is the most feared of all Talismans ever made.
Although it is not known who first created them it is believed that they originated in the Ayutthaya dynasty (1350-1767 AD), when it was recorded that the sacred warrior Khun Paen created such a weapon to protect himself from danger, ghosts and other malevolent forces, which it is thought could absorb and neutralize.

Khun Paen did not call his sacred knife as Mitmor, but “Darb Fa Fuen”, or sacred lightning sword, which was one of many sacred possessions he owned including Guman Thong, Hongprai (sacred lady) and Marsimok (sacred horse). This sword is now housed in the National Museum.
At that time it was also recorded that Khun Paen used several kinds of auspicious materials to create his sacred sword:

Steel from top of ancient chedi.

Steel from the top of ancient castles.

Steel from coffins

Steel formerly used to pull corpses during cremation.

Broken swords and lances

Leklai

Lek Namphi (special steel only mined in Namphi Uttaradit)
Gold, Copper and Silver
Moreover he also used Chaiyapurk wood to make the handle of his sacred knife into which he inserted the hair of Hongprai to increase the power further still. The handle of the knife was then engraved with sacred yant.

(Note: Hongprai was Khun Paen’s wife killed during pregnancy to create the Golden Boy known as Guman Thong)
Nowadays of course it is illegal to carry such weapons in public, and hence the mitmor has become popular as it can be easily concealed. (Some mitmor are only a few inches long.)