Gorath
Gorath was a legendary Klingon figure, who supposedly lived during the time of Kahless the Unforgettable, but before many of his exploits.
Gorath was a young man who had never engaged in battle, but called himself a warrior. One day, while traveling to Kalmuth to learn the ways of the Bat'leth, he encountered two bandits, Krak and Grack. They approached him, but he scared them off by displaying his Bat'leth.
When he returned home, his boasting of the tale was so great that it was reported to the powerful House of Bronal. The head of the house instructed assassins to kill Gorath to avoid risk to themselves. Gorath's entire family was killed.
Klingons telling Gorath's story would later theorize that if he had not boasted of his deeds, he might have fought with Kahless against Bronal. (ST episode: "Klingon Fable: The Legend of Gorath").