In the novel "The Spell Sword" Damon Ridenow sets a small matrix stone into the hilt of a sword. He realizes that by doing so he may, in theory, be violating The Compact, and that such matrix weapons are banned. He discovers that although he is no use in actual battle, being a poor swordsman, he can use the sword as a weapon in the Overworld, and thereby assist the soldiers "on the ground." Other swords, with larger matrices, are important weapons that figure in the novels.