"Metaphysics or Enchantment
This is a much discussed and debated topic of FMA. Technically, they are not weapons, but to the extent they can protect the owner from harm or wounds, or confuse or incapacitate the enemy, then they become accoutrements or instruments of war or combat. We are talking about amulets or charms (anting-anting) and prayers (orasyones).
Amulets are physical, such as human bones (sometimes dug up from graves), special stones, etc., while orasyones are special incantations, with spiritual attributes or powers, attributed to God with overtly religious references, oftentimes with specific goals, i.e., to confuse the enemy, to make the owner impervious to weapons, etc.
A most notable Grandmaster who believed in this was Antonio “Tatang” Ilustrisimo, who carried an amulet and had an “orasyon” tattooed across his chest. It must have worked for him, since he survived a lifetime of death matches and violent street encounters to live to a ripe old age of ninety-three."