The Omen
is a mysterious spirit and villain in the fifth Season 5 of Samurai Jack.

He resembles a ghostly black silhouette of an armored samurai with glowing eyes riding on a horse, surrounded by an ominous green fog. Up close, he appears to have no visible face and a hangman's noose around his neck. He also has a deep, dark voice. It is later revealed that the reason he haunts Jack is because he has neglected his purpose as a samurai, and insists that he commit ritual suicide of seppuku.