Gundar
Gundar was a Viking captain, noted for his viciousness and might in battle.
One day, he interpreted his crew asking him a question as a challenge to his authority and flew into a rage, attacking the entire crew by himself, sword in hand. The crewmen did not dare kill him, which would have been explicit mutiny by the viking code, but did wear him down until he had no strength or weapons left with which to fight. Instead of surrendering, Gundar invoked a curse on his crew, which only he or a descendant could choose to lift, before sailing away from the ship in a small boat, intent on drowning himself to ensure he would never have a change of heart and lift the curse, nor pass on knowledge of the curse's existence to his descendants.
However, despite this extreme measure, a 20th century descendant of Gundar found his way to the timeless island where Gundar's curse kept the sailors imprisoned, and after they told him their tale, he was able to wish them free. (COMIC: Dr. Who's Time Tales)