The brother of Kahless the Unforgettable, who in Klingon legend fought Kahless for twelve days and twelve nights after telling a lie that brought dishonour upon their family.
Morath is a figure of Klingon legend, the brother of Kahless the Unforgettable. Morath broke his word and shamed the family, and Kahless fought him for twelve days and twelve nights rather than let the lie stand. Klingons tell the story to teach that honour and truthfulness matter more than kinship.
Worf relates the legend to his son Alexander in The Next Generation episode New Ground, after the boy is caught lying and stealing aboard the Enterprise-D. A small metal statue of the two brothers locked in combat stands in Worf's quarters throughout the series and is the visual symbol of the tale; Alexander and Worf return to stories of Kahless in Firstborn.
Morath is never portrayed by an actor; he exists on screen only as that sculpture and in Worf's retelling.