"Terminus Est" is described as being "Light to raise, weighty to descend." This is due to (in addition to the obvious ethical quandary, in that raising the sword causes no harm, but the descending stroke ends a life by decapitation) a channel in the spine of the blade, containing liquid hydrargyrum, another name for mercury. (Wolfe makes use of obscure terms from Latin and Greek in many of his works, and in the New Sun Cycle additionally makes heavy use of French and Spanish.)