Jonah Hex is a Civil War veteran who became a bounty hunter. He is something of an anti-hero, however, as he has a good heart and, deep down, is a good person. When Noh-Tante - an Apache who Hex knew from earlier in his life - married a former love interest of Hex's, Hex believed he had betrayed him and the two fought. Noh-Tante sabotaged Hex's weapon for the fight and, as a result, was winning the battle. Hex was forced to kill him with a knife, which broke a sacred law forbidding the murder of an Apache. As a result, the Apache chief ordered several braves to hold Jonah down while the he was branded with the Mark of the Demon by pressing a boiling hot tomahawk to the right side of his face. The outcome was that Hex was hideously burned and scarred - to the extent that there was a hole in the side of his face.
