on a galactic scale
Y'ton was the name given to the duty an Immortal bore toward mortals according to Authlanis legend. Immortals could be so only if they had a y'ton. If an immortal forsook his or her y'ton, he or she ceased to be immortal.
However, a mortal could also have a y'ton, in which case the word would carry its most basic meaning of a sacred duty assigned by the Cosmos.